CN104364343A - Self-suspending proppants for hydraulic fracturing - Google Patents

Abstract

The invention relates to modified proppants, comprising a proppant particle and a hydrogel coating, wherein the hydrogel coating localizes on the surface of the proppant particle to produce the modified proppant. The proppant particles can be solids such as sand, bauxite, sintered bauxite, ceramic, or low density proppant. Alternatively or additionally, the proppant particle comprises a resin-coated substrate. Optionally, the modified proppant further comprises an adhesion promoter, optionally affixing the hydrogel coating to the resin-coated substrate. The hydrogel coating preferably comprises a water-swellable polymer. The hydrogel coating can be manufactured form a water soluble polymer. The preferred weight average molecular weight of the polymer is about 1 million g/mol, preferably about 5 million g/mol.

Description

For waterfrac treatment from-suspended prop

Technical field

The application's relate generally to is used for the system of fracturing technique, preparation and method.

Background technology

In the process obtaining oil and/or gas from well, usually need the flowing stimulating hydrocarbon through waterfrac treatment (hydraulic fracturing).Term " pressure break " refers to the method pumped into by fluid in well, until pressure is increased to the level being enough to pressure break and containing the subsurface geology stratum of (entrapped) material retained.This process causes the crackle and the fracture that damage lower floor, is carried into well boring to allow hydrocarbon product with remarkable higher speed.But unless kept pressure, otherwise the new aperture formed is closed.In order to open path and keep path, inject together with hydraulic fluid and support reagent or " propping agent ", to produce the support kept needed for aperture.When forming crack, propping agent transmits by during release hydraulic pressure in the slurry, and propping agent forms packing layer (pack) or the supporting layer (prop) for staying open crack at this.

Place (placement) propping agent in order to complete in inside, crack, suspended in a fluid by these particles, pump is to point of destination, underground subsequently.In order to prevent particles settling, high viscosity fluid is usually needed to carry out suspended particle.Usually by add synthesis or the viscosity that controls fluid based on natural polymkeric substance.Three kinds of common types of the enhancing by polymer fluid system suspending and carry propping agent are generally used for: slippery water (slickwater), linear gel and crosslinked gel in hydraulic fracturing operations process.

In slippery water system, usually add negatively charged ion or cationic polyacrylamide as friction-reducing agents additive (friction reducer additive), allow maximum fluid to flow with minimum pumping energy.Because the pumping energy of waterfrac treatment requires high (10,000-100, about 000 horsepower), in slippery water fluid, add friction-reducing agents, make that there is high pump rate, avoid needing even higher pumping energy simultaneously.Although these polymkeric substance are effective as friction-reducing agents, they are not efficient as tackifier and suspension agent.Slippery water polymers soln usually every 1000 gallons of (gallons) slippery water fluids contains 0.5-2.0 gallon friction-reducing agents polymkeric substance, and this solution has low viscosity, is generally about 3-15cps.Under this low viscosity, once turbulent flows stops, the proppant particles of suspension can easily settle from suspension.For this reason, slippery water fluid uses not having propping agent, in the pressure break stage with the propping agent of small particle size or low propping agent load.

The fluid system of the enhancing by polymer of the second type is called linear gel system.Linear gel system contains carbohydrate polymer usually, such as melon that (guar), Natvosol (hydroxyethylcellulose), hydroxyethyl melon that (hydroxyethyl guar), hydroxypropyl guar (hydroxypropyl guar) and hydroxypropylcellulose (hydroxypropylcellulose).These linear gel polymkeric substance add with the use speed of every 1000 gallons of linear gel fluid 10-50 pound (pounds) polymkeric substance usually.These concentration of linear gel polymkeric substance cause the fluid of the propping agent suspension characteristic relative to slippery water fluid with improvement.Be about the load level of 0.1-1 pound propping agent at per gallon fluid under, linear gel fluid is for carrying propping agent.Exceed this propping agent load level, usually need more viscous solution to prepare stable suspension.

Crosslinked gel is the fluid of the polymkeric substance-enhancing of most thickness type for carrying propping agent.In crosslinked gel systems, linear gel fluid as above is cross-linked with the reagent (such as borate, zirconate and titanate) added under basic metal exists.When linear gel fluid be cross-linked become crosslinked gel fluid time, viscosity is much higher, and propping agent can Effective Suspension.Linear gel and crosslinked gel fluid have some advantage, but they need the polymkeric substance of the costliness of high dosage speed.

Can be advantageously used in the modification of proppant particles and improve their performances in waterfrac treatment system.First, if proppant particles is more added with buoyancy, can use the suspension fluid of less viscosity, this still by particulate transportation to target area, but more easily can pump in stratum.The second, after propping agent has injected pressure break pipeline, in the whole time limit of service of well, expect that propping agent remains on the place of placement.If the change in the production period reservoir (reservoir) of well forces propping agent to leave position, production unit may be destroyed, and is blocked by the propping agent of displacement along with reservoir hole, and the conductivity of reservoir formation may decline.3rd, once place them in crack, the propping agent in system should resistance to closure stress.In some shale gas well closure stress can 1700psi to as high as and more than 15,000psi (hot hole for dark) scope.Must be careful, can not be malfunctioning in this stress lower support agent, in order to avoid they are crushed to the fine particle for can migrate to less desirable position in well, thus impact is produced.Desirably, during fracture treatment, propping agent should resistance to Diagn.High pressure and temperature and adversely can affect proppant particles for the combination of the chemical of fracturing fluid, cause their Diagn, along with the time, in the past this can final production thin particulate matter, and this thin particulate matter can scale out, and reduces the productivity of well.

Current propping agent system and the fracturing fluid of polymkeric substance-enhancing are devoted to solve that these are worried, propping agent can be carried by fracturing fluid, once reach their target point of destination, can keep in position, and can closure stress in resistance to stratum.A kind of method preparing suitable propping agent comprises use resin-coating proppant material.The propping agent of resin-coating can solidify or partially cured completely.By helping distributed stress in grain particles, completely crued resin can provide the crushing resistance to propping agent matrix.By encapsulating proppant particles, completely crued resin can also help to reduce fines (fine) migration.If partially cured at first, once be placed in crack, resin can become and solidify completely.The method can obtain the benefit same with using completely crued resin-phase when starting.But resin can reduce conductivity and the perviousness in crack, even if when propping agent keeps it to open.In addition, resin may be malfunctioning, and their advantage is lost.System based on resin is tended to costliness and is still easy to settle from suspension.

In addition, there is the health relevant to the treatment and processing of propping agent, security and environmental concerns.Such as, in naturally occurring sand settling, fine particle (" fines ") is usually found, such as crystalline silica dust.During treatment and processing propping agent sand, these fines can be used as the dust release that can suck.When long-term exposure, this dust may be harmful to workman, causes the various situation relevant to suction, such as silicosis (silicosis), chronic obstructive pulmonary disease, lung cancer etc.Except these healthy effects, fines can cause " public hazards dust " problem such as stained equipment and contaminate environment.

The method of the propping agent that another kind of preparation is suitable relates to makes additive mix with propping agent itself (such as fiber, elastic granule etc.).But additive can affect the rheological property of conveying slurry, makes it more be difficult to propping agent to be delivered to the position of the expectation in crack.In addition, additive is used can to disturb the even placement of the proppant mixture in pressure break position.Although this area exists the restriction that known method solves propping agent system, still there is some problem.Therefore; this area needs the propping agent system improved, and the propping agent system of this improvement allows accurately to place, keep fracture conductivity, protection well production efficiency after placement, equipment life, simplification hydraulic fracturing operations, reduce the impact of environment and promote workers ' health and security.Also expect that the system cost of such improvement is efficient.

Summary of the invention

The present invention relates to modification propping agent, described modification propping agent contains proppant particles and hydrogel coating, wherein, the surface of proppant particles localizes described hydrogel coating with production modification propping agent.This proppant particles can be that solid is as sand, bauxite, sintered bauxite, pottery or low-density propping agent.Alternatively, or in addition, described proppant particles contains the matrix of resin-coating.Optionally, described modification propping agent also contains the adhesion promoter of the matrix described hydrogel coating being optionally fixed on described resin-coating.The polymkeric substance of described hydrogel coating preferably containing water-swellable.Described hydrogel coating can manufactured formation water-soluble polymers.The weight-average molecular weight (weight average molecular weight) of described polymkeric substance is preferably >=about 1,000,000 g/mol, more preferably >=about 5,000,000 g/mol.Preferably, described propping agent is dry, is free-pouring after experiencing 1 hour at relative humidity 25-35 DEG C when drying and/or at about 80%-90%.Described hydrogel coating be preferably durable and have by shear analysis test determine >=the shearing ratio of 0.6.

The present invention relates to the method manufacturing propping agent and the propping agent produced by the method.Preferably, described hydrogel coating is applied on proppant particles also dry to form the film of basic continous on the surface at proppant particles with liquid coating preparation.Described modification propping agent can pass through reversed-phase emulsion paint-on technique (invert emulsion coating technique) preparation; wherein; described proppant particles matrix is combined with reversed-phase emulsion; wherein, oil phase forms the continuous print phase of emulsion and the solution of superabsorbent (superabsorbent) polymkeric substance in water or suspension form phase that is discontinuous, emulsification.

Described hydrogel coating is preferably containing the polymkeric substance be selected from by the following group formed: polyacrylamide, hydro-polyacrylamide, the multipolymer of acrylamide and the unsaturated ionic comonomer of ethylenic, the multipolymer of acrylamide and acrylate, poly-(vinylformic acid) or their salt, carboxymethyl cellulose, Natvosol, hydroxypropylcellulose, guar gum (guar gum), carboxymethyl guar, Carboxymethyl hydroxypropyl guar, the emulsion polymer (hydrophobically associating swellable emulsion polymers) of hydrophobic association swellable and emulsion polymer.The amount of described hydrogel coating can be less than 5 % by weight of gross dry weight (the total dry weight).

Described modification propping agent is preferably from suspending.The hydration of the preferred propping agent of the present invention in excessive water can stand the volumetric expansion of at least 100%, is preferably at least 500%.

Described modification propping agent can containing extra auxiliary material (excipients), such as anionic/cationic polymkeric substance pair, and this anionic/cationic polymkeric substance is to containing cationic polymers and high molecular weight anionic polymer.Described cationic polymers choosing can be selected from the group be made up of poly-DADMAC, LPEI, BPEI, chitosan and cationic polyacrylamide.

Described modification propping agent preferably with and/or also containing being oxidized gel breaker (oxidative breaker) or enzyme breaker is combined.Described oxidation gel breaker can be selected from by the following group formed: superoxide, Magnesium peroxide, calcium peroxide, persulphate, nitrate, bromate, ozone and oxychloride.Described oxidation gel breaker can be the cation-modified oxidation gel breaker that can be associated by ionization and hydrogel.Described enzyme breaker can be the positively charged ion enzyme breaker that can be associated by ionization and hydrogel.Described modification propping agent can also containing hydrophobic skin.Such as, described hydrophobic skin can be selected from by the following group formed: lipid acid, aliphatic amine, hydrophobic quaternary amine, aliphatic amide, winterized stearin, vegetables oil, Viscotrol C, triacetin, wax, polyethylene oxide (polyethylene oxides) and poly(propylene oxide).Alternatively, described modification propping agent can also containing the hydration additive postponed, such as low hydrophile-lyophile balance tensio-active agent, the repellents getting rid of covering with paint (finishing) tensio-active agent, ion crosslinking agent, covalent crosslinking agent and/or monovalent salt charge shielding agent.Described modification propping agent can also contain alcohol, the group that the optional freedom of described alcohol forms below: ethylene glycol, propylene glycol, glycerine, propyl alcohol and ethanol.In embodiments, modification propping agent according to claim 1, also containing anti-hard caking agent, such as hydrophobic layer material, fine particle material and/or linking agent.The example of anti-hard caking agent comprises Calucium Silicate powder, calcium carbonate, talcum, kaolin, wilkinite, diatomite, silicon-dioxide, colloid silica, Microcrystalline Cellulose (microcrystalline cellulose) and attapulgate (attapulgate).They also can comprise aerosil (fumed silica), Calucium Silicate powder, calcium carbonate, kaolin, wilkinite and attapulgate.Described hydrogel coating can contain additive, such as chemical additive or tracer agent.

Described modification propping agent preferably contains less fines than unmodified proppant particles.

The present invention includes waterfrac treatment preparation, described waterfrac treatment preparation contains modification propping agent as herein described and is oxidized gel breaker or enzyme breaker.The present invention also comprises the method for fractured well.These methods preferably include step:

Prepare waterfrac treatment preparation of the present invention, and

With effective volume and under the working pressure of waterfrac treatment, Xiang Jingzhong introduces described waterfrac treatment preparation,

Thus fractured well.

In embodiments, the method for fractured well, comprising:

The waterfrac treatment preparation of preparation containing modification propping agent of the present invention,

With effective volume and under the effective pressure of waterfrac treatment, Xiang Jingzhong introduces described waterfrac treatment preparation,

Gel breaker preparation containing oxidation gel breaker or enzyme breaker is provided, and

The described gel breaker preparation of effective volume is added in the well of effective volume,

Thus fractured well.

In method, described gel breaker preparation can before Xiang Jingzhong introduces waterfrac treatment preparation, among or join afterwards in well.Described gel breaker preparation can a step or multistep add.

In the process of the geo-logical terrain penetrated by well in pressure break, wherein, fracturing fluid (fracing fluid) containing propping agent is filled with in geo-logical terrain with pulsating pressure, the present invention includes the method for the amount for reducing the thickening material joined in fracturing fluid, this fracturing fluid contains selects modification propping agent of the present invention as propping agent.Modification propping agent of the present invention preferably substantially completes hydration, such as, in 10 minutes in first time in fracturing fluid was in conjunction with two hours.

The present invention includes the method manufacturing modification propping agent.These methods can comprise step:

Provide support the coating composition of agent blapharoplast and polymerizable fluid; With

Described propping agent blapharoplast applies the coating composition of described polymerizable fluid;

Optionally dry modification propping agent;

Wherein, the coating composition of described polymerizable fluid contains aquogel polymer, and, wherein, described aquogel polymer is localized with production modification propping agent on the surface of described propping agent blapharoplast.The step of described drying can the coating of dry described polymerizable fluid to form the film of basic continous on the surface of described modification propping agent.The method preferably occurs near the some place of the described modification propping agent of use or its, such as, produce sand, pottery, low-density propping agent, the matrix of resin-coating and/or the position of bauxite.The method can also be included in propping agent blapharoplast and fluid polymer coating composition mixing step during or add the alcohol be selected from by the following group formed before: ethylene glycol, propylene glycol, glycerine, propyl alcohol and ethanol.

During described method is preferably included in the step of propping agent blapharoplast and fluid polymer coating composition and/or anti-hard caking agent mixing or add reversion promotor (inversion promoter) afterwards.

The method manufacturing the propping agent of hydrogel coating also can comprise:

Provide support agent blapharoplast and the preparation containing coating precursor, wherein, described coating precursor can form hydrogel coating by in-situ polymerization on the surface of described propping agent blapharoplast;

Preparation is applied to described propping agent blapharoplast; With

The described coating precursor contiguous with described propping agent blapharoplast is polymerized the propping agent applied to form hydrogel.

Described method preferably produces the coated membrane of basic continous on the surface of described propping agent blapharoplast.

Accompanying drawing explanation

Fig. 1 shows the bottle of the sand (middle and the right) of sand (left side) uncoated in water and hydrogel coating.

Fig. 2 A-2C shows the MIcrosope image of hydrogel layer time dependent hydration on propping agent.

Fig. 3 is the schema of the manufacturing processed for certainly-suspended prop.

Fig. 4 (Fig. 4 A and 4B) display adds (4A) without glycerine and has glycerine to add the SEM image of the proppant particles of the hydrogel coating of (4B).

Fig. 5 shows the SEM image of hydrogel coating dry on the surface of proppant particles.

Fig. 6 is the figure of bed height relative to shear time of three groups of certainly-suspended prop samples.

Fig. 7 is the figure of bed height relative to mixing time of two groups of certainly-suspended prop samples.

Fig. 8 is the figure of bed height relative to mixing time of two groups of certainly-suspended prop samples.

Fig. 9 be after a series of process from the bed height of-suspended prop sample figure relative to mixing time.

Figure 10 adds the figure of the different Calucium Silicate powder measured to the bed height of certainly-suspended prop sample.

Figure 11 be a series of preheating and the bed height of propping agent sample of non-preheating relative to the figure of time of drying.

Figure 12 display bed height is at various temperatures relative to the figure of time of drying.

Figure 13 show after a series of process from the temperature of-suspended prop sample figure relative to mixing time.

Figure 14 shows bed height and (LOI) figure relative to time of drying is lost in igniting.

Embodiment

1, modification proppant particles

Disclosed herein is, for the formation of with using, there is the system and method for the proppant particles of hydrogel surface layer, to strengthen the hydrodynamic volume of proppant particles during fluid conveying, the target point of destination of the expection in crack can be arrived at propping agent before, the more stable proppant slurry produce resistance to sedimentation, being separated and sifting out.Other benefit of the propping agent of hydrogel coating disclosed herein comprises comparatively low propensity ground etching apparatus, frictional coefficient lower under wet condition, combination good each other after being placed on location of cracks adheres to, the formation of resistance to not controlled fines, and the fouling resistance character being attributable to water-wetted surface.In embodiments, the type of the most widely used propping agent matrix can be applied to for the formation of the system disclosed in proppant particles, such as, the sand of sand, resin-coating, bauxite, low-density propping agent and pottery.In other embodiments, proppant particles can be formed by the available multiple matrix of those of ordinary skill in the art, comprises fibrous material.In some embodiments, can proppant particles be manufactured, make their resistance to crushing or distortion, make their resistance to displacements, and they can be suspended in the fluid carrier of less viscosity for being delivered in stratum.

The present invention includes a kind of modification propping agent, described modification propping agent contains proppant particles and hydrogel coating, wherein, the surface of proppant particles localizes described hydrogel coating with production modification propping agent.In embodiments, these certainly-suspended props are formed by using polymeric coating (such as hydrogel) the modified particles matrix of water-swellable.In embodiments, before being incorporated in fracturing fluid by particle-matrix, polymer coating layer modification particle-matrix can be used.In embodiments, based on the weight of propping agent, the amount of aquogel polymer coating can in about 0.1% to about 10% scope.In embodiments, the hydrogel layer be applied on the surface of propping agent matrix can have the coat-thickness of about 0.01% to about 20% of propping agent matrix mean diameter.When hydrogel layer in fracturing fluid hydration and swelling time, water can make hydrogel layer variable expansion, make expand hydrogel layer variable thickness be about 10% of propping agent matrix mean diameter to about 1000%.Fig. 1 shows the image of three bottles, propping agent containing identical amount in the water of each bottle, wherein, the bottle on the left side contains the propping agent not having hydrogel coating, middle bottle contains the propping agent of 1% hydrogel coating, and the bottle on the right contains the propping agent of 3% hydrogel coating.In each bottle, propping agent is mixed with water, then do not carry out stirring sedimentation 24 hours.The bed volume of the sedimentation of the propping agent of hydrogel coating is significantly greater than the bed volume of the sedimentation of uncoated propping agent, and this propping agent showing that hydrogel applies keeps suspending in water.Fig. 2 A, 2B and 2C show the light microscope image of the propping agent crystal grain of three identical hydrogel coatings respectively, and wherein, each image obtains after the propping agent hydration different time of hydrogel coating in water.In fig. 2, the proppant particles in water 15 seconds of hydrogel coating; In fig. 2b, the proppant particles in water 45 seconds of hydrogel coating; In fig. 2 c, the proppant particles in water 120 seconds of hydrogel coating.As shown in these figures, along with the increase of hydration time, hydrogel layer volume increases rapidly and significantly expands with size.

Although known to using super water absorption polymer coating propping agent in the prior art; to form hydrogel coating (reference on single proppant particles matrix; such as; U.S.2008/0108524), preparation disclosed herein and method are different from these technology in important and favourable mode.As disclosed herein, the aqueogel used has some outstanding character.More specifically, preparation disclosed herein comprises to be selected and is applied to the hydrogel of proppant particles, to form modified particles, this mode makes: (a) when drying, free-pouring, and/or, b () is when with water hydration, hydrogel coating is durable and/or hydrogel coating volumetric expansion makes the volume at least large 20% of the modification propping agent of the volume ratio drying of the modification propping agent of hydration, or the volume about 20% of the modification propping agent of ratio drying is to about 50%, or the volume about 50% of the modification propping agent of ratio drying is to about 100%, or the volume about 100% of the modification propping agent of ratio drying is to about 200%, or the volume about 200% of the modification propping agent of ratio drying is to about 400%, or 400% of the volume of the modification propping agent of ratio drying is also large.

As used herein term " dry ", when the moisture content of modification propping agent be 1 % by weight or less time, modification propping agent is considered to dry.Preferably, when drying, the moisture content of modification propping agent of the present invention is≤0.5 % by weight or even≤0.1 % by weight.In embodiments, the thickness of the hydrogel coating of the drying on modification propping agent can be less than 10 microns, and is usually less than 2 microns.In embodiments, aquogel polymer in aqeous suspension and excessive tap water (tap water) contact at 20 DEG C can in 2 hours, or in 1 hour, or in 30 minutes, or in 10 minutes, or in 2 minutes or even basic hydration completely in 1 minute.As used herein, the propping agent of the hydrogel coating described as " completely basic hydration " refers to that the volume increasing amount of the propping agent that hydrogel applies is at least 80% of the cumulative volume increasing amount of the propping agent that hydrogel applies when in water during complete hydration.

In embodiments, when drying, will be free-pouring according to the modification propping agent that these preparations and method are formed, any caking or reunion can easily disperse by stirring gently.If modification propping agent demonstrates caking to a certain degree or reunion, but these cakings and reunite and can pulverize by stirring gently, still will think that described modification propping agent is free-pouring.

The volumetric expansion of propping agent can be determined by the analytical test (a Settled Bed Height Analytical Test) of the bed height using sedimentation.Such as, in the vial of a 20mL, the modification propping agent of drying to be measured for 1gm is joined in 10gms water (such as, tap water) at about 20 DEG C.Then this bottle about 1 minute (such as, by repeatedly overturning bottle) is shaken to make wetting modification propping agent coating.Then this bottle is left standstill, until aquogel polymer coating has become hydration.The bed height formed by the modification propping agent of hydration can measure by using Digital caliper (a digital caliper), then the bed height that formed divided by the propping agent by drying of this bed height, the gained numeral volumetric expansion factor (multiple).In addition, conveniently, the bed height formed by the modification propping agent of hydration can compare with the bed height formed by uncoated propping agent, as shown in embodiment 5 below.

Coating wearing quality can measure in shear analysis test (the Shear Analytical Test) below.Such as, 1L water (such as, tap water) is joined square 1L beaker (this beaker have about 1.25 liters cumulative volume and with the interstitial wire of 1L mark).Then beaker is put into an EC engineering CLM4 paddle mixer (EC Engineering CLM4 paddle mixer).This mixing machine is set to mix with 300rpm.Once mixing starts, the modification propping agent to be measured of 50gm is joined in beaker in a dried form.After mixing 30 seconds under 300rpm, mixing rate is reduced to 200rpm and is continued to be mixed to the hydration of aquogel polymer coating.Then mixture is poured into also sedimentation in the 1L cylinder of calibration, carries out the measurement of the bed height of the sedimentation of modification propping agent afterwards according to mode mentioned above.Then the bed height (" having the bed height of the sedimentation of shearing ") of this sedimentation is compared with the bed height (" bed height without the sedimentation of shearing ") not standing the sedimentation of the modification propping agent of the hydration of this shearing treatment of identical amount.The amount being reduced the bed height of the sedimentation of modification propping agent by this shearing treatment is that of the wearing quality of its hydrogel coating measures.For object of the present invention, if there is the bed height of the sedimentation of shearing to be at least 0.2 with the ratio (" shearing ratio ") of the bed height without the sedimentation of shearing, hydrogel coating is then considered to durable.Demonstrate be greater than 0.2, be more than or equal to 0.3, be more than or equal to 0.4, be more than or equal to 0.5, be more than or equal to 0.6, be more than or equal to 0.7, be more than or equal to 0.8 or the modification propping agent that is more than or equal to 0.9 be all desired.

As noted above, type and the amount of the aquogel polymer of the use in modification propping agent disclosed herein can be selected, make the factor of the volumetric expansion increase at least 1.2 of modification propping agent, as determined in the bed height analytical test by above-mentioned sedimentation.In a specific embodiment, as described in Example 5, this factor can be more than or equal to about 3, about 5, about 7, about 8 and even about 10.

Also as noted above, when drying, modification propping agent of the present invention is free-pouring.In a specific embodiment, though these modification propping agents experience high humidity after be also free-pouring, as find, such as, the Summer Solstice (mid-summer's day) of southern US.In order to this object, modification propping agent to be measured can experience the humidity measurement of 1h under 80-90% relative humidity, 25-50 DEG C condition.After these humidity measurement conditions of experience, remain free-pouring modification propping agent be considered to be even free-pouring after experience high humidity.

Method for propping agent modification is included on propping agent matrix sprays or saturated liquid polymer formulations, then dry, with except anhydrating or other carrier fluid.By applying heat or vacuum, and by upset or whip modified propping agent during drying process, drying process can be accelerated.Heating can be applied by forced hot air, convection current, friction, conduction, burning, thermopositive reaction, microwave heating or ir radiation.During propping agent modifying process, stir have to provide in proppant material evenly the further advantage of coating.

Fig. 3 diagrammatically illustrates according to the manufacturing processed 100 for the preparation of certainly-suspended prop 130 of the present invention.In the described implementation, sand 132 (such as, there is the dry sand being less than 0.1% moisture) be transported in mixing vessel 124 via travelling belt 122, and liquid polymer composition 120 is sprayed onto on sand 132 along travelling belt 122 via pump and spreading nozzle equipment 134.The sand 132 being exposed to liquid polymers 120 reports that (reports) is to low sheraing mixing vessel 124, wherein, composition is blended further, to form modification sand 128.After mixing, the modification sand containing liquid polymers is delivered to moisture eliminator 126, to remove the water and/or organic carrier fluids that associate with liquid polymers 120.After the drying step, dry modification sand 132 is through finalization step 134, and this finalization step can involving vibrations device and/or other size classes equipment such as be sieved, to remove the aggregate (agglomerate) of oversized dimensions.Finalization step 134 also can make dry modification sand 132 experience mechanical mixer, shear, shredder, grinding mill etc., to pulverize aggregate, thus allows material through the sieve of appropriate size.Finished-product material 130 stores subsequently and is used for shipment or uses.

In embodiments, before use aquogel polymer modification, by for the production of from the sand of-suspended prop or the predrying moisture content to <1% of other matrix, and preferred <0.1%.In embodiments, when mixing with liquid polymers, sand or other substrate temperature within the scope of about 10 DEG C to about 200 DEG C, preferably about 15 DEG C to about 80 DEG C scopes or 15 DEG C to 60 DEG C.

In embodiments, by sprinkling or injection, propping agent matrix is contacted with liquid polymer composition.The add-on of liquid polymer composition in about 1 % by weight to about 20 % by weight scopes of sand weight, preferably about 2 % by weight to about 10 % by weight.By the time period of propping agent matrix and the blended 0.1-10 of liquid polymers minute.In a preferred embodiment, mixing equipment is the mixing machine of relative low sheraing type, such as turner, vertical conical screw rod blender, v-circular cone blender, double cone blender, pugging mill (pug mill), paddle mixer or banded blender.In embodiments, mixing equipment can be equipped with other instrument forced air, forced hot air, vacuum, indirect heating or cause carrier fluid to evaporate.

In embodiments, the modification propping agent matrix containing liquid polymers is dry, to remove the water and/or organic carrier fluids that associate with liquid polymers.Moisture eliminator equipment can be conveyor oven (conveyor oven), microwave or rotary kiln type.In one embodiment, carry out drying step, its mode makes dry modification sand contain the liquid of the remnants being less than 1 % by weight, contains the water and any organic carrier fluids that associate with liquid polymer composition.

In embodiments, identical equipment can be used for making propping agent matrix and liquid polymers blended, and the single process segment or in continuous seepage pipeline the product of dry blend.

In other embodiments, the method for propping agent modification comprise hydrogel coating fabricated in situ or under the existence of proppant particles, cause hydrogel layer to encapsulate the surface of proppant particles.Such as, the fabricated in situ of hydrogel can by then carrying out polymerization procedure to realize by proppant particles and coating precursor monomer and/or macromer incorporation.In other illustrative example, water-soluble polymers can be dissolved in monomer, has or solvent-free, is then polymerized under proppant particles exists, causes the formation of the polymer network of the IPN as the coating on propping agent.In other illustrative example, water-soluble polymers is dispersed in monomer, has or solvent-free, and, the propping agent of the hydrogel encapsulation that polymerization subsequently will cause the water-soluble polymer particles locked by the polymkeric substance newly formed to form.Monomer used or macromonomer can be selected from the monomer causing water-soluble polymers.In other illustrative example, can non-soluble polymer encapsulated particles be passed through, then by this non-soluble polymer modification or hydration to obtain water-soluble hydrogel coating.As one of ordinary skill in the understanding, encapsulated layer can be had or be formed by different polymerization technique under condition of no solvent.The in-situ polymerization of the polymkeric substance on the surface of propping agent crystal grain has the advantage reducing or eliminating drying step.

For example, water-soluble monomer for hydrogel coating or in-situ polymerization can be selected from following monomer or their salt: vinylformic acid, methacrylic acid, acrylamide, Methacrylamide and their derivative, propyloic acrylic ester, hydroxyethyl methylacrylate (HEMA), Hydroxyethyl acrylate (HEA), polyethylene glycol acrylate (PEG-acrylate), NIPA (NiPA), 2-acrylamido-2-methyl isophthalic acid-propanesulfonic acid (AMPS), the sodium salt of styrene sulfonic acid, vinyl sulfonic acid, (methyl) allyl sulphonic acid, vinylphosphonic acid, N-vinyl acetamide, N-methyl-Nvinylacetamide, N-vinyl formamide, N-methyl-N-vinylformamide, NVP, N-butyrolactam or N-caprolactam, maleic anhydride, methylene-succinic acid (itaconic acid), vinyl-acetic ester, dimethyl diallyl ammonium chloride, quaternised dimethylaminoethyl methacrylate (quaternized dimethylaminoethyl methacrylate, DMAEMA), (methyl) acrylamidopropyl trimethyl ammonium chloride ((meth) acrylamidopropyltrimethylammonium chloride), methylvinyl imidazolium villaumite (methylvinylimidazolium chloride), 2-vinyl pyridine, 4-vinylpridine etc.Can the ratio of Selective ion mode monomer and non-ionic monomer to obtain the hydrogel with different charge densities.In some cases, such as, in order to obtain the coating with fast hydrating or swelling property, the hydrogel obtaining there is higher electric charge is expected.In one embodiment, with the molecular fraction of monomer for benchmark, the ion content of aquogel polymer or electric density are the nonionic of ion within the scope of 10-70% and surplus.In a preferred embodiment, take molecular fraction as benchmark, the electric density of aquogel polymer is in the scope of 25-55%.Ionic monomers in other example can be selected from has higher or lower ionization constant (ionization constant) to obtain the hydrogel of higher or lower stability under saltwater environment.Other advantage character can by selecting suitable electric density to give.

In embodiments, coating precursor can comprise containing multiple polymerizable groups and in hydrogel, introduce multifunctional monomer that is crosslinked or tapping point.The example of these monomers is: pentaerythritol triallyl ether, polyethyleneglycol diacrylate and methacrylic ester, N, N'-methylene-bisacrylamide, Epicholorohydrin, divinylsulfone and glycidyl methacrylate.When using these monomers, cross-linking monomer can within the scope of the 0.001-0.5% of total monomer content.Select the scope adding linking agent, should be noted that and add excessive linking agent, such as, be greater than the amount of the 0.001-0.5% of total monomer content, the frangible hydrogel that pressure splits or degrades can be formed in.In embodiments, add linking agent and can form the under extreme conditions unlikely hydrogel be separated from particle surface.

In embodiments, the monomer/macromonomer of use is selected from the coating precursor monomer that can form non-water-soluble coating.After applying coating, further modification will cause the polymkeric substance of water-swellable.Such as, the coating of the polymerization containing hydrolization group can be formed, and hydrolysis will obtain hydrogel subsequently.The example belonging to the monomer of this class is ester, acid anhydrides, nitrile and acid amides; Such as ester monomer can use methyl acrylate, tert-butyl acrylate.As another example, the monomer containing vinyl function can had or solvent-free lower formation hydrogel by different polymerization technique.Described polymerization technique comprises body, suspension, Admicelle (admicellar), solution polymerization.

In other embodiments, can select coating monomer or precursor with formed the hydrogel that has containing urethane or polyureas from-suspended prop.The list forming the monomer be applicable to urethane and/or polyureas functional polymer is: polyhydric alcohols is as ethylene glycol, propylene glycol, glycerine, TriMethylolPropane(TMP), 1,2,6-hexanetriol, tetramethylolmethane, Sorbitol Powder, sucrose, Alpha-Methyl glucosides, polyoxyethylene glycol is PEG, PEG-PPG multipolymer, pluoronics (Pluronics), season ketone (Tetronics) such as, and polyamine is polyetheramine (Jeffamines) such as.That can mention in isocyanic ester has tolylene diisocyanate, naphthalene diisocyanate (naphthalenediisocyanate), Xylene Diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylene diisocyanate, trimethyl hexamethylene diisocyanate, cyclohexyl-1,2-vulcabond, cyclohexylidene-Isosorbide-5-Nitrae-vulcabond etc.Other suitable polymkeric substance can comprise Dow company hydrophilic polyurethane prepolymer, Bayer company with resin (2,4'-diphenylmethanediisocyanate, 4,4'-diphenylmethanediisocyanates and their mixture), and Cytec company (prepolymer of the polyisocyanic acid functionalization of tolylene diisocyanate and poly-(tetramethylene ethylene glycol)) etc.

The coating with the proppant particles of urethane (PU) hydrogel can be realized by ordinary method.In one embodiment, this coating is carried out under can not using solvent in the body.Such as, a kind of exemplary formulations for crosslinked PU hydrogel can be prepared in a step bulk polymerisation process by using vulcabond, polyoxyethylene glycol and a polyfunctional crosslinking agent.In one embodiment, said preparation is by the polyoxyethylene glycol containing 10-80%, and the molecular weight of this polyoxyethylene glycol is between 200-25000.

Then the method that another kind of original position forms hydrogel layer can be undertaken by monomer polymerization in monomer formulation by dissolving or water in suspension soluble polymer.The list of the water-soluble monomer before described monomer can be selected from.When water-soluble polymer dissolves is in monomer mixture, the polymkeric substance formed by initial water-soluble polymers and original position in the hydrogel network of IPN forms by gained coating.When water-soluble polymers is suspended in monomer mixture, the hydrogel coating by the water-soluble granular locking or retain wherein forms by gained coating.Such as, these particles can wrap in the new hydrogel coating formed inner or they can be incorporated on the new polymkeric substance formed.Water-soluble polymers can have or be dissolved or suspended under solvent-free existence in monomer formulation and polymerization can be undertaken by different technology.

The suitable water-soluble polymers mixed with monomer can be selected from by the following group formed: the emulsion polymer, starch, emulsion polymer etc. of the multipolymer of polyacrylamide, polyacrylic acid, acrylamide and acrylate, polyoxyethylene glycol, Polyvinylpyrolidone (PVP), polyvinyl alcohol, carboxymethyl cellulose, Natvosol, hydroxypropylcellulose, guar gum, carboxymethyl guar, Carboxymethyl hydroxypropyl guar, hydrophobic association swellable.

The method of modifying of another kind of proppant particles comprises the hydrophilic polymkeric substance of chemical graft on particle.The polymer chain be grafted on the surface of particle can by having come to the reaction on particle surface such as Hu Yisigen (Huisgen) cycloaddition and other coupling or addition reaction by fixed polymer.

Proppant particles for these objects can select to have surface functional group as epoxy group(ing), vinyl, amine and hydroxyl etc.Then these groups can react with the polymkeric substance with the group that can react with the functional group on particle surface.Such as, the proppant particles containing silicon-dioxide can carry out surface modification by silane such as aminosilane, vinyl silanes, epoxy radicals silicone hydride etc.

In embodiments, the polymkeric substance reacted with the particle of functionalization is hydrophilic straight or branched polymkeric substance or multipolymer.Polymkeric substance can have one or more graft sites.In embodiments, polymkeric substance can have the functional group as amino, carboxyl or their salt, hydroxyl, sulfydryl, acid anhydrides, acyl chlorides and/or isocyanate groups, and this functional group can be covalently bond to the functional group of particle.Can be used for having with the example of the polymkeric substance of the particle reaction of functionalization: the polyoxyethylene glycol, polymine, polyacrylic acid, polyvinyl alcohol etc. of Epoxy-functionalized polyoxyethylene glycol, the polyoxyethylene glycol of amino-functionalization, azide functionalization.

In embodiments, the hydrogel of gained, except having swellable character, can have temperature response or pH response property.Therefore the swellable character of propping agent can adjust.This is extra benefit propping agent being delivered to well boring downwards, because temperature is lower and fully swelling behavior is desired at the initial stage of conveying propping agent; The higher temperature of inside, crack is desired, in order to improve filling in crack, expects the lower swelling of hydrogel layer.The monomer of the propping agent applied for the preparation of the hydrogel of temperature response can be selected from NIPA (NiPA), oxyethane, propylene oxide or show the macromonomer/polymkeric substance of minimum critical solution temperature (LCST).

In one embodiment, the process that matrix is transformed into certainly-suspended prop as sand can be carried out, such as, in the oil well or the gas well position that prepare waterfrac treatment near use point place or its.The method has the following advantages: the consumer goods materials (such as sand) of higher material processing cost is converted into the special material with additional features.Sand can be obtained by local resources or directly load and transport from sand mining area or warehouse, for locating modification at use point.This avoid must first by sand shipment extremely blended factory, and secondary is from the shipment of blended factory to use point subsequently.When sand, shipment cost may, higher than material cost, therefore in order to control cost, avoid extra shipment to be desired.

In a kind of exemplary manufacturing processed, sand and modifying chemical can be joined continuous mixer.After completion of the mixing, mixture can (a) prepare use or (b) deliver to drying step.Drying step can comprise heated drying process or process of vacuum drying, and it can comprise and adds anti-hard caking agent.Finished product can be stored in the container at well position.An example of mixing equipment is continuous band-shaped blender or pugging mill.Drying step can be the process independent of mixing, and can design drying step to avoid the excessive shear such as conveyor or tunnel dryer of finished product.The drying machinery device of other type comprises rotary kiln, microwave dryer, blade dryer and vacuum drier.

Can introduce and can be used for the aquogel polymer of modification according to the propping agent of system and method disclosed herein, in embodiments, as oil based emulsions, suspension, water-base emulsion, latex, solution and dispersion.In embodiments, the emulsion that aquogel polymer can be used as distillation is introduced, and such as part evaporation removes the oil based emulsions of a part of carrier fluid.Compared with the emulsion of routine, this advantage that the drying of reduction can be provided to require.In embodiments, aquogel polymer can be the emulsion of alkali swellable, and wherein, the hydrogel properties of polymkeric substance is until polymkeric substance contacts with alkali is just developed completely.In this embodiment, the emulsion of alkali swellable can be coated to form modification propping agent on propping agent matrix, and under basic material exists, this modification propping agent can be suspended in fracturing fluid.

In embodiments, propping agent blapharoplast and liquid polymers coating composition mixing step during or before, additive can be added and be such as selected from by the alcohol of the following group formed: ethylene glycol, propylene glycol, glycerine, propyl alcohol and ethanol.In embodiments, useful reversion promotor can be used as the additive in the polymeric coating preparation of certainly-suspended prop, reversion promotor can comprise high HLB tensio-active agent, such as Pluronic F-127 lauryl alcohol tensio-active agent (polyethylene oxide lauryl alcohol surfactant, the ETHAL LA-12/80% of ETHOX company), ethylene glycol, propylene glycol, water, sodium carbonate, sodium bicarbonate, ammonium chloride, urea, bariumchloride and their mixture.In embodiments, promotor of reversing can be played and be promoted that active polymer content enters the release action (usually moisture) pending process fluid mutually in oil based emulsions polymkeric substance.Because oily continuous print polymkeric substance is reversed to water continuous print environment by this process, phase reversion can be characterized as being.

In other embodiments, propping agent matrix can use polymer formulations modification, without the need to drying step.This has come by using not solvent-laden polymer formulations or curable preparation.In the method that some simplifies, dry or liquid polymers preparation can be applied on propping agent matrix via on-line mixing, and therefore obtainedly material modifiedly can to use without the need to processing further.By adding or change except anhydrating or add other liquid the moisture content of propping agent matrix, to allow matrix effectively to be applied, process, and be delivered in fracturing fluid.

Modification propping agent can also use wetting agent such as tensio-active agent or other hydrophilic material modification, to allow effectively to be distributed in fracturing fluid.When hydrogel-modification propping agent is suspended in fracturing fluid, if they need comparatively low viscosity fluid to settle from suspension to prevent particle, they are considered to certainly-suspend.

Modification propping agent can also in the course of processing, transport and storage modification to improve its mobility and handling properties.Can flow by the bulk solid of negative impact modification propping agent by making modification propping agent reunite in some cases in the surface of the moisture absorption of modification propping agent, particularly evident in humidity and/or high humidity environment.Modification propping agent anti-caking character can be given to reduce or eliminate reunion by further modification, described modification can be passed through in processing, transported and reduce the hygroscopic tendency of modification propping agent in storage process or pass through processing, transporting and reduce the surface action between adjacent modification propping agent in storage process, or both simultaneously.In embodiments, once be joined by modification propping agent in the aqueous fluid of end-use application, anti-hard caking agent can not affect the estimated performance of modification propping agent.Described modification propping agent can with the such as finely divided solid of anti-hard caking agent or second outer or both process.Described second skin can be the modification proppant surface that crosslinking degree is low, or the non-moisture absorption layer of solid, or positively charged ion salt deposit, or the hydrophobic layer of oiliness or their combination.Use the modification propping agent of anti-hard caking agent can have the handling properties of raising, such as unrestricted flow character, agglomeration resistance, easily carrying, easily measure and be easy to draw off from storage or transport container.In embodiments, use the modification propping agent of anti-hard caking agent can reduce dry needs, thus can reduce manufacture a finished product energy, time and equipment amount.

In embodiments, anti-hard caking agent is the finely divided solid containing clay, material, organism, metal oxide or soap.In other embodiments, anti-hard caking agent is that finely divided solid is as Calucium Silicate powder, Magnesium Silicate q-agent, calcium carbonate, talcum, kaolin, wilkinite, attapulgite (attapulgite), diatomite, silicon-dioxide, colloidal silica, aerosil (fumed silica), W-Gum, carbon black, Microcrystalline Cellulose, ferric oxide, aluminum oxide, calcium stearate, Magnesium Stearate or their combination.

In embodiments, described anti-hard caking agent is the second skin formed by the surface of cross-linking modified propping agent.Add the material that can be cross-linked the polymkeric substance of swellable in proppant surface and effectively can reduce polymer layer ability swelling too early.The polymers swell reduced will reduce modification propping agent in the trend of transporting and experience caking in storage or reunite.In embodiments, cross-linked material has the ability forming key with hydroxyl functional groups, carboxy functional group, amine functionality or acid amides functional group.Cross-linked material can be selected from the organic compound containing aldehyde, amine, acid anhydrides or epoxy functional groups.Cross-linked material also can be organometallic compound (organometallic compounds).In embodiments, the key that cross-linked material is formed can destroy or remove under mechanical shearing.Can to associate with hydroxyl and carboxy functional group and/or the organometallic compound of Cheng Jian is the example of the cross-linked material forming shear-sensitive key.Under the high-shear of the pump associated with waterfrac treatment, crosslinked on polymkeric substance can be degraded, and once be introduced in hydraulic fracture fluids by modification propping agent, this polymkeric substance just can be swelling without barrier.

In embodiments, described anti-hard caking agent is the thin second layer of solid non-hygroscopic material, the multipolymer of non-absorbent material such as lipid acid, hydrogenated fatty acid, winterized stearin, wax, polyethylene, polyethylene oxide, poly(propylene oxide), polyethylene oxide and poly(propylene oxide), or their combination.The example being suitable as the lipid acid that the second layer uses comprises stearic acid, palmitinic acid, lauric acid or contains stearic acid, palmitinic acid/or lauric tallow fatty acid.The example being suitable as the winterized stearin that the second layer uses comprises Viscotrol C.The example being suitable as the wax that the second layer uses comprises paraffin, vaseline (petroleum jelly) and slack wax.Thin solid layer can be applied to the surface of modification propping agent to set up an obstacle preventing the polymer layer of the swellable on adjacent modification proppant particles from adhering in storage.Solid skin used can be made up of water-soluble, water-insoluble or compound both.Described solid skin is non-hygroscopic.Described solid skin is selected to make it still keep solid-phase temperature less than 38 DEG C and have the fusing point within the scope of 40-120 DEG C.In embodiments, selection is outer makes enough low the making in outer drying process in modification propping agent manufactures of fusing point be liquid phase, and the enough high skin that makes of fusing point stores at modification propping agent and exists with solid-phase in transport.The outer obstacle as the caking of the modification propping agent stoping/reduce environment through moisture to cause of solid-phase.Solid skin can join in modification propping agent with finely divided powder, thin slice, solution in oily carrier or warm liquid.Described solid skin can before polymkeric substance, with polymkeric substance simultaneously, as the blend with polymkeric substance, or can join in modification propping agent certain time after polymkeric substance adds but before drying process.Preferably, described solid skin anti-hard caking agent to add after polymkeric substance fully mixes with modification propping agent before dry modification propping agent.

In embodiments, described anti-hard caking agent is the second layer of the salt of univalent cation electric charge, the salt of univalent cation electric charge can join in modification propping agent as liquid or the solution in oil temperature less than 100 DEG C, such as cats product or unit price salt hydrate.Cats product contains Adogen 464 that the quaternary amine with hydrophobic afterbody is such as purchased from Akzo Nobel or Arquad 2HT-75 can be used as the second coating to provide the hydrophobic layer of modification propping agent, simultaneously also can in and the current potential anionic charge (potential anionic charge) of polymkeric substance.Many salt hydrates, such as sodium acetate trihydrate and aluminium sodium sulfate dodecahydrate, have lower than 100 DEG C fusing point and can to join in modification propping agent and to melt as the second layer in the drying process of modification propping agent.In two kinds of situations of cats product and salt hydrate, the enriched layer of the cationic charge in modification proppant surface, can reduce the swelling current potential of the polymkeric substance of negatively charged ion charging.When modification propping agent is introduced current, monovalent salt can fully dilute to allow modification propping agent to run according to expection.

In embodiments, the described anti-hard caking agent be applied on modification propping agent is hydrophobic, the lubricating oil second layer, is selected from by the following group formed: silicone oil, mineral oil, vaseline, triglyceride level or their combination.The example being suitable as hydrophobic, that the lubricating oil second layer uses silicone oil comprises polydimethylsiloxane (polydimethylsioxane).The example being suitable as hydrophobic, that the lubricating oil second layer uses triglyceride level comprises Semen Maydis oil, peanut oil, Viscotrol C and other vegetables oil.Preferably, hydrophobic lubricating oil has smoke point and boiling point higher than manufacturing the temperature that propping agent drying stage uses.Preferably, the smoke point of this oil is higher than 200 DEG C.Preferably, the smoke point of this oil is at least 175 DEG C.

Contrary with making the moderately viscous traditional method of whole fluid, hydrogel of the present invention-modification propping agent advantageously can use the polymer concentration of localization in proppant surface.Such as compare with the fracturing fluid (such as slippery water, linear gel and crosslinked gel) of the polymkeric substance-enhancing of routine, the hydrogel layer of this localization can allow more effectively to use polymkeric substance, makes the polymkeric substance of lower total amount can be used for suspended prop.Although think hydrogel-modification propping agent from-suspend, they can use with friction-reducing agents, linear gel and crosslinked Gel Compositions.

Hydrogel disclosed herein-modification propping agent can have the following advantages: send friction-reduction polymkeric substance to fracturing fluid, make, when hydrogel-modification propping agent is for hydraulic fracturing operations, may not need or may need other friction-reducing agents polymkeric substance of small amount.In embodiments, some aquogel polymers can from the surface desorption of propping agent, to send the benefit or viscosity characteristics that friction reduces to fracturing fluid.Although illustrative embodiments herein concentrates on the application of the hydrogel-modification propping agent for waterfrac treatment object, but be envisioned other purposes of hydrogel-modification propping agent, wherein, can be developed them for keeping moisture or reducing the ability rubbed.Such as, hydrogel-modification propping agent may be used for absorbing water from wet environment, forms the particle of the maintenance moisture that can remove from environment, takes away their less desirable moisture.Another example, hydrogel-modification propping agent can be used in and add the situation that in water to environment, meeting is favourable.Hydrogel-modification propping agent can with water or the saturated rear use of the aqueous solution, such as, as soil remediation additive in dry environment.Hydrogel-modification propping agent can be formed by sand or other matrix compatible with soil, and they can be transported to object region (the area of interest) in a dry form; Then with water saturation, they are also used as soil improvement agent.In other embodiments, hydrogel-modification propping agent can be used as soil improvement agent in a dry form, and wherein, they can from environment, from irrigation, adsorb and keep humidity from rainfall etc.In these embodiments, the character of the maintenance moisture of hydrogel-modification propping agent can be favourable use.In embodiments, hydrogel-modification propping agent may be used for the corrosion reducing topsoil, seedbed, spray grass mixture (hydroseeding mixtures) etc.In embodiments, hydrogel-modification propping agent can be used as the vehicle (vehicle) be incorporated into by other compatilizer in region, such as, be incorporated in soil.Hydrogel-modification propping agent can containing when hydrogel degraded or when its absorbs moisture when expanding, hydrogel layer leaching or the extra preparation that passes through in hydrogel layer entered environment.The example of these preparations comprises fertilizer, seed, plant-growth regulator, weedicide, sterilant, mycocide etc.Other purposes of the hydrogel-modification propping agent prepared according to these preparations and method can be envisioned, consistent with their character described herein.

In embodiments, aquogel polymer for the preparation of hydrogel-modification propping agent can contain polymkeric substance such as polyacrylamide, the multipolymer of negatively charged ion and cationic comonomer acrylamide, the polyacrylamide (hydrolyzed polyacrylamide) of hydrolysis, the multipolymer of acrylamide and hydrophobic comonomer, poly-(vinylformic acid), poly-(vinylformic acid) salt, carboxymethyl cellulose, Natvosol, hydroxypropylcellulose, guar gum, alginate, carrageenan (carrageenan), Viscogum BE (locust bean gum), carboxymethyl guar, Carboxymethyl hydroxypropyl guar, emulsion (HASE) polymkeric substance of hydrophobic association swellable, emulsion polymer, starch etc.In embodiments, aquogel polymer can have the molecular weight (g/mol) higher than 1,000,000, such as 1,000 ten thousand-4,000 ten thousand daltonian scopes.In embodiments, aquogel polymer can be water-soluble and have the vinyl-addition polymer of the high molecular of linear structure.

In embodiments, aquogel polymer described above can be cross-linked, and absorbs and swelling property with the water strengthening polymkeric substance.The key element that linking agent can be used as hydrogel based polymkeric substance is introduced, or the chemical modifier that they can be used as preformed polymkeric substance is introduced.Cross-linked material can directly join in coating propping agent polymkeric substance used, joins simultaneously and have in the propping agent of polymkeric substance while mixing, or certain time after polymkeric substance joins propping agent but before it is dried adds.

Polymkeric substance can be caused more effectively to utilize around proppant surface localization polymkeric substance described herein, and can prevent propping agent from settling from polymers soln.In embodiments, polymer layer, around propping agent hydration, effectively prevents propping agent/propping agent (between particle) from contacting.This can prevent propping agent from forming fine and close sedimentation bed, and propping agent can be caused more easily again to be suspended in fracturing fluid.If interrupt fluid flowing during hydraulic fracturing operations, the settling flux character of modification propping agent may be important.In this case, when recovering when flowing, propping agent can settling flux to avoid losing propping agent or the block fluid path do not anticipated is important.

When polymers swell, polymer surface modification described herein can cause the effective fluid power radius of proppant particles to improve.This can cause the resistance (drag) that improves on propping agent and effectively change total water gel/pellet density.The two all can cause the proppant particles with slower subsidence rate and excellent transport properties.

Hydrogel of the present invention-modification propping agent advantageously can use the polymer concentration of localization in proppant surface.Preferably, in hydrogel hydration after being exposed to the shearing condition as pipeline transportation, a large amount of aquogel polymers still associates in proppant surface in water.In embodiments, the physics of polymkeric substance can be caused by the manufacturing processed of aquogel polymer coated substrates particle or be chemically attached in proppant surface.This attachment can be caused by the winding of polymer chain when dried hydrogel film, can prevent the hydrogel coating of desorption when causing being exposed to the shearing under hydration status.In embodiments, the interaction of chemical reaction or polymer chain helps the winding of polymer chain.In embodiments, linear, non-cross-linked hydrogels polymkeric substance can be used as coating, become winding to make linear polymer chain when polymeric coating is formed.In embodiments, by drying process in the mill and the winding by using coalescing aid (coalescing aid) to help polymkeric substance.Described coalescing aid is cause the coalescent additive becoming continuous film of the single emulsion droplets of coating agent when drying.In embodiments, described coalescing aid is alcohol such as propyl alcohol, glycerine, propylene glycol or ethylene glycol.Fig. 4 A and 4B shows two electronic scanning micrograms (SEM), illustrates that glycerine is agglomerated into impact in continuous film causing coated polymeric.In electronic scanning microgram Fig. 4 A, with the aqueogel coating propping agent of anionic polyacrylamide emulsion not adding glycerine, then at 100 DEG C dry 1 hour.In the image of Fig. 4 A, the coating that propping agent grain surface is complete can be seen, but the single emulsion droplets being about 1 micron diameter remains visible.In the SEM image of Fig. 4 B, with the aqueogel coating propping agent adding the anionic polyacrylamide emulsion having the glycerine of 10 % by weight as coalescing aid, then at 100 DEG C dry 1 hour.It is obvious that coalescing aid affects in the outward appearance of desciccator diaphragm: the coating that the SEM image display propping agent crystal grain in Fig. 4 B is substantially complete, and in this case, emulsion droplets is agglomerated into continuous print film more.Fig. 5 shows the SEM image of dried hydrogel film prepared by the method identical with the sample of Fig. 4 B.Aquagel membrane display emulsion droplets film coalescence preferably in Fig. 5, and proppant particles surface covers completely.

In embodiments, polymer pair, optionally connects with ion pair and closes, and can be used for improving the delay of aquogel polymer on the surface of proppant particles (retention).Such as, cationic polymers can be used as the first layer and is deposited on propping agent, " to be locked in place " by ion coupling by the second layer containing hydrogel (such as high molecular weight anionic polymer).In embodiments, cationic polymers can be diallyl dimethyl ammoniumchloride (poly-DADMAC), L-PEI (LPEI), the polymine (BPEI) of side chain, chitosan, epichlorohydrin/dimethylamine polymers, ethylene dichloride dimethylamine polymer or cationic polyacrylamide.Before or after use anionic hydrogel layer modification proppant surface, cationoid polymerisation nitride layer can be placed on propping agent.Ion coupling interacts and can be used as grappling mechanism, to contribute to preventing anionic polymer desorption in high shear environment, such as, by pump or during being pumped down to well boring.By causing the extension postponing hydration and anionic polymer chain, cationic polymers also can improve polymer retention.Believe that polymer chain less during pumping procedure extends and will obtain higher polymer retention (that is, less desorb) on propping agent.

In embodiments, the covalent cross-linking of the hydrogel polymer layer in proppant surface can improve the swelling property of polymkeric substance and shear tolerance to prevent water gel from discharging too early from propping agent.Covalent crosslinking agent can comprise following functions group: epoxide, acid anhydrides, aldehyde, vulcabond, carbon diamide (carbodiamides), divinyl or diallyl group.The example of these covalent crosslinking agent comprises: polyethyleneglycol diglycidylether, Epicholorohydrin, maleic anhydride, formaldehyde, oxalic dialdehyde, glutaraldehyde, tolylene diisocyanate, methylenediphenyl diisocyanates, 1-ethyl-3-(3-dimethylamino-propyl) carbon diamide and methylene-bisacrylamide etc.The covalent cross-linking of the hydrogel polymer layer in proppant surface effectively can produce " the polymkeric substance cage " of swellable around propping agent.Covalent linkage prevents the complete desorption of polymkeric substance from entering solution.Slight insoluble polymer layer can the polymer layer of swelling and production hydration.

In order to stop hydrogel from the separation of particle surface further, proppant particles can be processed and make to give the function also participating in polymerization process.Such as, sand grains can by silane treatment to obtain the particle with vinyl function, hydroxyl functional, epoxy group(ing) function etc.

Can expect the delay of polymer layer/controlled hydration with propping agent process and postpone the hydration of polymer surface modification during being pumped across well boring at first.Environmental factors (such as humidity and rain) can cause the premature hydration of the coating of polymerization, and this can make to be difficult to effectively metering during hydraulic fracturing operations, enter the propping agent dosage of blender.Also believe that the polymer layer of complete hydration can be easier to desorption under the shear conditions associated with downward tubulose pumping fracturing fluid.For those reasons, the surface-modified propping agent with hydration that is slower or that postpone can advantageously be designed.In embodiments, the hydration postponed can be realized in the following manner: by adding low hydrophile-lyophile balance (HLB) tensio-active agent, high HLB coating surface promoting agent repellents, reduce deliquescent comonomer, use monovalent salt charge shielding agent or by mixing hydrophobic layer (such as lipid acid or fatty alcohol).

In embodiments, hydrophobic group can be incorporated in aquogel polymer, to allow hydrophobic interaction.The method can improve the salt tolerance of hydrogel layer, even if make hydrogel layer also still keep swellable in the aqueous fluid containing the salt concn raised.

Object due to hydrogel coating is the hydrotransport in order to improve propping agent, and the hydrogel layer of the hydration when being exposed to shearing condition in fluid transport keeps attachment or be localised on the surface of propping agent being very important.But when being placed in fractured well by the propping agent that hydrogel applies, aquogel polymer should degrade or unclamp with from propping agent die separation, and obtain the propping agent packing layer with abundant hydraulic conductivity and can fluid be produced.The existence of the temperature such as raised by environmental factors, microbial process and gel breaker, salt solution and/or hydrocarbon thus cause removing of propping agent hydrogel layer.In a preferred embodiment, be pumped to after in well by the propping agent that hydrogel applies, hydrogel is degraded, unclamps, dissolves or is separated under the help of gel breaker as oxygenant or enzyme.The gel breaker of oxidant type can be superoxide, Magnesium peroxide, calcium peroxide, persulphate, sodium bromate, clorox, ozone, SODIUMNITRATE etc.The propping agent that first oxygenant (such as ammonium persulphate) of low-temp activation and the blend of second oxygenant (such as Magnesium peroxide) of activated at can apply at hydrogel improves the destructiveness of hydrogel after placing.Enzyme base gel breaker well known in the art is normally used for reducing the viscosity pumping into FIH.Enzyme can promote the reaction of degraded or cutting polymer key (polymer linkage).In some cases, enzyme breaker can provide more effective destruction, because their targets bond aquogel polymer.Enzyme breaker is usually more effective under low temperature to middle temperature, and can be combined with the oxygenant of activated at.Based on the identity of aquogel polymer and downhole condition, select suitable enzyme breaker can improve the destruction of hydrogel.

There is disclosed herein a kind of use hydrogel to apply propping agent and the method for propping agent combination fracturing well of non-aqueous gel-coating.Such as, the propping agent of hydrogel-coating can serve as the suspension agent of the propping agent for non-aqueous gel-coating.

In a specific embodiment, selecting aquogel polymer to make at least to carry its hydration in time that this aquogel polymer arrives its point of destination at modification propping agent is substantially completely.In embodiments, the point of destination that down-hole applies is the region that in well, modification propping agent enters the geo-logical terrain treating pressure break, such as, the direction of travel of hydraulic fracture fluids is from vertical to the region of level transition, or the direction of drill string starts the region from vertical to level transition.Especially can utilizing in the hydraulic fracture fluids of common level direction movement from-suspension characteristic of the preferred modification propping agent of the disclosure.In embodiments, select to be used for the aquogel polymer of modification propping agent to make to contact at 20 DEG C with excessive tap water in 2 hours, in 1 hour, in 40 minutes, in 30 minutes, in 20 minutes or even in 10 minutes, hydration is completely substantially.

There is disclosed herein a kind of propping agent using hydrogel to apply and placed with the method improving well productivity by the propping agent improved.The far-end that the propping agent that hydrogel applies more effectively can be delivered to crack is to guarantee higher to come the oil of artesian well and the productivity of gas.Because surface-modified propping agent disclosed herein is not easy to settle from fluid, and easier settling flux and being transported by crack, it will be more effective for believing that propping agent is placed.Ability propping agent being transported to further crack can significantly improve the effect of pressure break stimulation applications, causes the higher density crack of comparatively large vol.These fissure channel can advantageously allow gas/condensation product easier from the boring of reservoir inflow well.

There is disclosed herein a kind of method of the improvement using the propping agent of low viscosity fluid to place.Surface modification propping agent disclosed herein can more effectively utilize polymkeric substance to suspend/transporting proppant particle.Surface modification make propping agent from-suspend, thus reduce or eliminate needs to highly viscous fluid/gel transporting proppant.Therefore, can combinationally use with surface-modified propping agent, with transporting proppant in crack compared with low viscosity fluid.This will advantageously simplify the preparation of the fracturing gel used together with propping agent.

There is disclosed herein the more effective method using less propping agent fractured well.Highly effective propping agent can be realized owing to using the surface-modified propping agent that can easily transport disclosed herein to place, compared with using the system of traditional propping agent, for any given fracturing operation, expect and will need these surface-modified propping agents of small amount.The reduction of the sand supply of the raising due to the requirement for pressure break rank sand/propping agent and the expectation-shape for propping agent application, those system and methods are as disclosed herein provided to be favourable, wherein, less propping agent can be used to realize with the result using current techniques quite or than excellent result.

After being pumped in well by the propping agent that hydrogel of the present invention applies, hydrogel layer is by chemistry, heat, machinery and biomechanism degraded.Particularly, by chemical gel breaker, such as, ammonium persulphate, Magnesium peroxide or other oxygenant, can destroy the surface modification that propping agent is polymerized.By environment reservoir conditions, the brine content such as raised, the temperature of rising and contact with hydrocarbon, also can destroy the surface modification that propping agent is polymerized.When reaching target temperature or time quantum in fluid, the controlled destruction of hydrogel layer can be used as the mode that guide support agent is placed on the desired location in crack.The degraded of hydrogel layer is also useful for guarantee the enough conductivities in the crack completing hydraulic fracturing operations rear support.In embodiments, provable stimulation-the response property of hydrogel layer, to make when being exposed to the first set condition (such as some the first temperature or pH) itself and water-soluble swollen, and when experiencing a certain set condition (such as the second temperature or pH), it loses water, loss volume, loses thickness or even caves in.

Such as, in one embodiment, temperature-response water gel can be coated in proppant material.When being exposed to water under the first set condition (such as the water temperature of 50-100 °F), the hydrogel layer swellable of temperature response, subsequently when being exposed to the second set condition (such as the water temperature of 110-450 °F), it can cave in.Use this stimulation-Response Mechanism, the propping agent of the hydrogel coating of temperature response can have certainly-suspension character, because under initial water temperature (such as 50-100 °F), fracturing fluid carries the position that propping agent enters subterranean fracture.When the propping agent applied runs into higher temperature region (such as the 110-450 °F) of subsurface formations, hydrogel layer can cave in, and allows propping agent deposit in crack and consolidate.The hydrogel of temperature response can be containing being selected from by the water-soluble polymers of the hydrophobic monomer of the following group formed or copolymer compositions: alkyl acrylate, N-alkyl acrylamide, propylene oxide, vinylbenzene and caprolactam (vinylcaprolactam).N-AAM can be NIPA, N-dibutyl acrylamide (N-butylacrylamide), N-octyl acrylamide etc.Alkyl acrylate can be replaced by the alkyl chain with from 1 to about 30 carbon.In a preferred embodiment, the aquogel polymer of temperature response contains NIPA and contains the hydrophilic comonomer unit of at most about 90%.The substituent type of hydrophobic monomer in aquogel polymer and amount are selected by assay optimization technology, to regulate water solubility and the temperature response character of aquogel polymer.

There is disclosed herein a kind of by blast blending in the hydrogel layer of modification propping agent, in propping agent packing layer, send the method for additive such as chemical additive.Additive can comprise the chemical additive advantageously can sent via hydrogel layer and comprise Scale inhibitors, sterilant (biocide), gel breaker, wax contrast, asphaltene contrast and tracer agent.Chemical additive can be the forms such as water-soluble material, water-insoluble particle, fiber, metal-powder or thin slice.Chemical additive can be selected to make them slowly dissolve or decompose, to discharge their chemically reactive.

In embodiments, such as, by covalent linkage, ionic linkage, hydrophobic association, hydrogen bond or encapsulating, chemical additive can be chemically bonded on the polymkeric substance in hydrogel layer.Chemical additive can join in propping agent independent of hydrogel, or they can manufacture coating propping agent time and hydrogel coating formulation compositions.Gel breaker chemical can be added, such as persulphate, superoxide, permanganate, perchlorate, periodates or percarbonate by this delivering method.Use the propping agent transport of hydrogel coating and send these chemical and have chemical targeted delivery to the advantage of crack or propping agent packing layer.This method provide in the advantage of position concentrating chemical additive needing their functions, thus can more fully, more efficiently and send chemical additive with low concentration.In embodiments, the desorption of aquogel polymer, oxidation or degraded can cause chemical additive from the Co ntrolled release from-suspended prop.

In embodiments, hydraulic fracturing operations can have multiple pressure break stage; The propping agent injected in each stage can containing unique (unique) chemical additive as tracer agent.Tracer agent is used in waterfrac treatment usually, comprises and high performance liquid chromatography (HPLC), gas-chromatography (GC), ultraviolet or visible absorbance and emission signal measurement can be adopted to detect tracer agent.The analysis of the fluid produced from fractured well can provide information about each pressure break stage relative productivity by the existence of tracer agent of the uniqueness in correspondence stage and concentration.In other embodiments, the additive as gel breaker can carry in the hydrogel layer, such as, by physical bond or be wrapped in polymer layer.In embodiments, the coating modified gel breaker of cationic surface can be used to provide attachment gel breaker to the grappling mechanism on the anionic hydrogel from-suspended prop.Such as, can with the cationic polymers such as coated magnesium oxide powder of poly-DADMAC, and the propping agent that this cation-modified Magnesium peroxide can apply with hydrogel is blended before or after propping agent is incorporated into waterfrac treatment current.Make in this way, gel breaker is transported to the position identical with hydrogel propping agent, and therefore, gel breaker can target aqueous gel layer effectively.Oxidation gel breaker at high temperature can have the activity of quickening.Make in this way, when the gel breaker chemical mixed in hydrogel layer can be placed in crack, to become activation, such as, by improving petroleum reservoir temperature.

In other embodiments, before or after the propping agent introducing hydrogel coating, gel breaker can be pumped to subsurface formations.By gel breaker before propping agent when pumping, after propping agent reaches its point of destination, the fluid containing excessive gel breaker will be flowed back to by propping agent packing layer and have the ability helping hydrogel layer degraded.When gel breaker being pumped to after proppant support stratum, gel breaker can permeate propping agent packing layer and have the effect puncturing hydrogel layer.In embodiments, gel breaker can repeatedly add to help to destroy hydrogel layer.In embodiments, gel breaker can use with the array configuration of type, such as, the gel breaker (such as ammonium persulphate) of low-temp activation may be used for rapid action, combinationally use with the gel breaker (such as Magnesium peroxide) of encapsulating, longer effect or activated at, fluid backflow and well start production for the previous period to provide the effect of creep rupture hydrogel layer.

In embodiments, the surface of proppant particles matrix can apply selectable polymkeric substance, as simple layer or as a series of multiple coating.Coating (simple layer or multilayer) can show disposable behavior in some cases.Term used herein " disposable behavior " or " conversion behavior " refer to the change of the character when situation changes, and such as, become another group character of inside, crack from one group of character during the haulage stage.Such as, when particle is presented at hydrophilic character in fracturing fluid and when being placed on the sticking property in crack, can see conversion behavior.By the behavior as triggered in the situation of the inner high confining pressure of location of cracks, the skin of coating itself is reset, to present character advantageously.

In one embodiment, when when inside, crack experience high pressure, the particle of coating can from hydrophilic be transformed to hydrophobic.In one exemplary embodiment, during the haulage stage, when the hydrophilic coverture of particle is exposed to Water-base fracturing fluids, it tends to complete expansion.As a result, coating can provide the particle with lubrication in this condition, promote that it moves by propping agent slurry.Although when by particle transport to point of destination in the crack in stratum time, will the steric exclusion of the polymer chain of external hydrophilic be overcome in this high pressure, forces outer itself rearrangement, internal layer is exposed.In embodiments, disposable internal layer can be hydrophobic or adhere to, or the two has concurrently.When internal layer exposes, the character of itself can display.If internal layer has the character of adhesion, such as, it can make particle be fixed to one another to prevent them from refluxing.This internal layer also can be set to trap fines when proppant particles is malfunctioning.In addition, the complete hydrophilic group being present in the remnants in external coating (EC) can allow oil easily to flow through propping agent packing layer.

In embodiments, the proppant particles carried with the coating of the coating of lower floor can be produced.The first, the fixing agent polymkeric substance of pressure-activation can be used for coating propping agent matrix.This coating can be elastic, thus provides intensity by helping to assemble proppant particles and distributed stress for propping agent packing layer.In addition, this coating can enclosing substrate particle and be retained in matrix malfunctioning when any fines of producing.The second, segmented copolymer is adsorbable or be arranged in addition on the first layer of coating.Multipolymer can have the part relative to the layer of the first polymerization with high-affinity, allows strong interaction (hydrophobic interaction), and can have another hydrophilic part, make easy transporting proppant in transporting fluid.

In some embodiments, between the first coating and the second coating may be useful compared with strong interaction.In order to realize this point, can implement swelling-remove swelling techniques.Such as, segmented copolymer can be adsorbed onto on the surface of the particle of elastomer coated.Subsequently, can use swelling first coating of a small amount of organic solvent, this organic solvent allows the hydrophobic block of multipolymer deeper to infiltrate in the first coating and is wound around in elastomer coating.By removing organic solvent, the mixture of the polymerization of stratification will go swelling, cause multipolymer and the stronger interaction of elastomer particles.Available for swelling-go the method for swelling techniques to be described in the people such as " for the preparation of polymeric colloid that is stable, functionalization based on swelling method (Swelling-Based Method for Preparing Stable; Functionalized Polymer Colloids) " A.Kim, J.Am.Chem.Soc. (2005) 127:1592-1593, its content is incorporated to herein by reference.

In embodiments, the propping agent system of use coating disclosed herein can reduce the amount of the airborne particle associated with propping agent manufacture.Such as, between propping agent processing period, can be trapped and the dust (comprising fine crystalline silicon dioxide dust) sucked keeping associating with treatment and processing propping agent sand by propping agent coating.In embodiments, coating agent particle in the environment that adversely may affect worker safety or produce public hazards dirt problems to specific avidity can be added in.In embodiments, by mechanical retention or adhere to dust granule, the hydrogel coating on proppant particles can serve as tackiness agent or trapping agent.

Although system described herein relates to two layers of coatings system, be understood that, can exist multiple (namely, more than two) form the coating of mixture proppant particles disclosed herein, each of wherein multiple coating has the some or all of characteristics of two coatings as above, or the one or more of multiple coating provide extra character or characteristic.

Add and in proppant surface, can effectively can reduce polymer layer ability swelling too early by the material of cross-linked polymers capable of swelling.The trend of the caking that the swelling propping agent reducing polymer-coated of polymkeric substance reduced experiences between the wet condition shelf lives.In some embodiments, once be dispersed in aqueous fluid by the propping agent of polymer-coated, such as, in hydraulic fracture fluids, linking agent can not hinder the hydration of polymeric coating/swelling.In embodiments, cross-linked material has with carboxy functional group, acid amides functional group or forms the ability of key with both.In some aspects, the key that cross-linked material is formed can destroy or removing under mechanical shearing or the effect passing through chemical gel breaker.Cross-linked material directly can being joined for applying in the polymkeric substance of propping agent, joining while mixing simultaneously and having in the propping agent of polymkeric substance, or certain time after polymkeric substance joins propping agent but before it is dried adds.

Described cross-linked material can be selected from the organic compound containing aldehyde, amine, acid anhydrides or epoxy functional groups.Described cross-linked material also can be a kind of organometallic compound.Can to associate with carboxy functional group and/or the organometallic compound of bonding is the example forming shear-sensitive key cross-linked material.In such embodiment, before propping agent can be incorporated in hydraulic fracture fluids by organometallic compound by crosslinked carboxy group to reduce the swelling tendencies of the propping agent of polymer-coated.Then, when crosslinked polymeric coating runs into the high shear force that pump into relevant with waterfrac treatment, can crosslinked on degradation polymer, when propping agent being incorporated into hydraulic fracture fluids to allow polymkeric substance expedite swelling.

In some embodiments, thin non-hygroscopic coating can be applied to the surface of the propping agent of hydrogel coating to set up an obstacle preventing the polymer layer of the swellable on adjacent modification proppant particles from adhering in storage.Skin used can be made up of water-soluble, water-insoluble or compound both.In embodiments, formulating described skin makes it below 40 DEG C, still keep solid-phase and have the fusing point within the scope of 40-120 DEG C.Preferably, formulate described skin make that fusing point is enough low the outer propping agent in polymer-coated manufactured in drying process in be liquid phase, and fusing point is enough high the outer propping agent in polymer-coated is stored and exists with solid-phase in transport.

In these embodiments, described skin reduces the obstacle of the propping agent caking applied in wet environment.As used herein, term " caking " refers to that loose granulated material adheres to the structure of block or the solid piece formed.Between the shelf lives, the caking of propping agent is that institute is less desirable for material processing object.Hydrophobic skin can join in the propping agent of polymer-coated with finely divided powder or liquid.In embodiments, cladding material can be melted before joining the propping agent of coating; In other embodiments, cladding material can add with solid or wax-like materials, and it can melt in drying process.Solid skin can join propping agent with polymkeric substance simultaneously or can add certain time after polymkeric substance adds but before drying process.Described skin can be made up of lipid acid, winterized stearin, vegetables oil, Viscotrol C, wax, polyethylene oxide, poly(propylene oxide) etc.

2, particle-matrix material

Various propping agent blapharoplast can be used to be formed according to the mixture proppant particles of these system and methods.Material, resin material, elastomeric material etc. and their combination of the sand of classification, the sand of resin-coating, bauxite, stupalith, glass material, walnut shell, polymerization can be comprised for proppant particles matrix of the present invention.Disclosed hereinly Special support agent also can be used prepare from-suspended prop (" SSP "), the sand of such as ceramic, bauxite and resin-coating.By being combined by sand SSP and special SSP, propping agent injection can have favourable intensity, perviousness, suspension and transport properties.In embodiments, matrix can comprise naturally occurring material, such as shred, grind, pulverize or crush to suitable dimension nutshell (such as, English walnut, Semen Caryae Cathayensis, coconut, almond, ivory nut, Bertholletia excelsa etc.), or such as shred, grind, pulverize or crush to the seed hull of suitable dimension or fruit core (such as, plum, olive, peach, cherry, apricot etc.), or such as from the material shredding, grind, pulverize or crush of other plant (such as corn cob).In embodiments, matrix derived from the timber of timber or processing, can include but not limited to timber such as Oak Tree, Semen Caryae Cathayensis, English walnut, mahogany, white poplar etc.In embodiments, use organic materials engage with inorganic materials or combine, can aggregate be formed.Expect that proppant particles matrix contains the particle (no matter being single material or the aggregate of two or more materials) of the size with size of mesh 4-100 (U.S. Standard mesh number) left and right.Term used herein " particle " comprises the material of all known form, such as but not limited to the material of sphere material, elongation, polygonal materials, filamentary material, irregular material and their any mixture.

In embodiments, particle-matrix can be used as mixture and is formed by tackiness agent and filler material.Suitable filler material can comprise inorganic materials such as solid glass, glass microspheres, flying dust, silicon-dioxide, aluminum oxide, gas-phase carbon, carbon black, graphite, mica, boron, zirconium white, talcum, kaolin, titanium dioxide, Calucium Silicate powder etc.In some embodiments, can strengthen proppant particles matrix, to improve the high pressure on their resistance to stratum, this high pressure can crush or make them to be out of shape.The optional self energy of strongthener is that proppant particles matrix increases those materials of structural strength, such as high strength particle, as pottery, metal, glass, sand etc., or can combine other material any to provide additional strength with particle-matrix.

Except expose or except the matrix that do not apply, the propping agent of mixture hydrogel coating can be formed by the matrix of the process lived through above or coating.Such as, the proppant particles of various resin-coating is well known to those skilled in the art.Above-mentioned preparation for applying and method be suitable for coating or the proppant particles that process use, comprise and solidifying or the propping agent of resin-coating of Procuring.

In a kind of embodiment for the treatment of the sand of resin-coating, as mentioned above, the hydrogel layer of swellable, to improve its suspension characteristic on the sand that can be applied to resin-coating.In embodiments, the material added as adhesion promoter hydrogel being attached to resin layer can be comprised.Adhesion promoter can be, such as, by the hydrophilic segmented copolymer formed with hydrophobic monomer.Described segmented copolymer can add as resin coating after resin-coating matrix sand or simultaneously.Except block copolymerization beyond the region of objective existence, cationic substance such as fatty amine, poly-quaternary amine and cats product can be used.

In some embodiments, proppant particles matrix can be used as the aggregate manufacture providing two or more differing materials of different nature.Such as, have high compression-strength slug particle matrix can with than high-to compress-strength materials has more low-density buoyant combination of materials.The combination of this bi-material can provide the slug particle with appropriate intensity as aggregate, have relatively low density simultaneously.As comparatively low-density particles, it fully can suspend in the fracturing fluid of less viscosity, allows the easier pumping of fracturing fluid, and due to them by the fluid forces of less viscosity to farther region, allow propping agent more to disperse in stratum.High density material (such as sand, pottery, bauxite etc.) as proppant particles matrix can combine with comparatively low density material; described is such as material and the naturally occurring material (nut shell, seed hull, fruit core, timber or other the naturally occurring material having shredded, grind, pulverize or crushed) of hollow glass particle, other hollow slug particle, some polymerization compared with low density material, is still had the aggregate that the density of enough compressive strengths is less.

Use the technology two kinds of components be attached to each other, the aggregate being suitable as proppant particles matrix can be formed.As a kind of preparation method, can by proppant particles matrix and the buoyant material mixing with the particle diameter similar with the size of proppant particles matrix.The particle of two types can mix subsequently; and combined by adhesive agent (such as wax, novolac resin etc.); make to form the paired aggregate particle of a group; subgroup has the proppant particles matrix that the particle similar with another adheres to; a subgroup has the proppant particles matrix adhered to buoyant particle, and subgroup has the buoyant particle that buoyant particle with another adheres to.Three subgroups are separated by their density difference: the first subgroup is sunk in water, and the second subgroup keeps suspending in a liquid, and the 3rd subgroup is by floating.

In other embodiments, proppant particles matrix can be designed, make its density less by the surface covering particle-matrix with foam materials.The thickness of foam materials can be designed, to obtain the mixture of neutral buoyancy (neutrally buoyant) effectively.In order to produce the proppant particles of such coating, the particle with the compressive strength of expectation can be coated with the reactant for foamable reaction, is then exposed to other reactant.When triggering formation of foam, by the proppant particles of production foam-coating.

As an example, full water foamed polyurethane foam can be used for providing coating by reducing overall particle density around particle.In order to prepare the particle of such coating, particle can initial application to respond thing A, the such as mixture of one or more polyvalent alcohols and suitable catalyzer (such as, amine).This particle can be exposed to the reactant B containing vulcabond subsequently.Final foam will be formed, such as, when using steam treatment under vibration on particle; Owing to forming foam over their surface, stir and will prevent particle aggregation.

In embodiments, fiber (comprising biodegradable fiber) can join in fracturing fluid together with SSP.Fiber (comprising biodegradable fiber) can form the fibre network helping fluid to carry propping agent.Multiple fiber type is familiar with by the professional and technical personnel for joining fracturing fluid.As professional and technical personnel to understand, the fiber joining fracturing fluid can be degraded under downhole condition, and forms passage in propping agent packing layer.Passage then has higher perviousness, and therefore this passage is hydrocarbon marches to well boring flow passage from stratum.

Term " fiber " can refer to fiber or the natural fiber of synthesis.Term used herein " fiber of synthesis " comprises fiber or the primitive fiber of all or part of manufacture.Synthesis fiber comprise regenerated fiber, here by natural precursor material modification to form fiber.Such as, Mierocrystalline cellulose (derived from natural materials) can be formed as regenerated fiber, such as artificial silk (Rayon) or Lyocell fibers (Lyocell).Also correctability Mierocrystalline cellulose, to produce estron.These regenerated fibers are the example of the fiber of synthesis.The fiber of synthesis can be formed by the material of inorganic or organic synthesis.The fiber of exemplary synthesis can be formed by the material of such as substituted or unsubstituted rac-Lactide, glycollide, poly(lactic acid), polyglycolic acid or their multipolymer.Form the polymkeric substance that other material of fiber comprises oxyacetic acid or the multipolymer formed with it, as professional and technical personnel be familiar with.

Term used herein " natural fiber " refers to derived from natural origin without the fiber of artificial modification or primitive fiber.Natural fiber comprises the fiber of (vegetable-derived) fiber, animal-derivative fiber and the mineral of plant-derivative-derivative.Plant-derivative fiber can be mainly Mierocrystalline cellulose, such as, and cotton, jute, flax, hemp, sisal hemp, ramie etc.Plant-derivative fiber can comprise the fiber derived from seed or seed housing, such as cotton or kapok.Plant-derivative fiber can comprise the fiber derived from leaf, such as sisal hemp and Folium Agaves variegatae.Plant-derivative fiber can comprise the fiber of crust derived from the stem around plant or bast, such as flax, jute, mestha (kenaf), hemp, ramie, rattan, soybean fibers, climing fiber (vine fiber), jute, mestha, industrial hemp, ramie, rattan, soybean fibers and banana fiber.Plant-derivative fiber can comprise the fiber of the fruit derived from plant, such as coconut fiber.Plant-derivative fiber can comprise the fiber of the bar (stalk) derived from plant, such as wheat, paddy rice, barley, bamboo and grass.Plant-derivative fiber can comprise wood fibre.Animal-derivative fiber contains protein usually, such as, and wool, silk, mohair (mohair) etc.The fiber of animal-derivative can derived from animal hair, such as, and the wool, goathair, Aloysia gratissima alpaca, horsehair etc. of sheep.The fiber of animal-derivative can derived from animal body part, such as, and catgut (catgut), tendon (sinew) etc.Animal-derivative fiber can be collected in saliva or other movement (excretion) of the drying of insect or their cocoon, such as, and the silk obtained by silk cocoon (silk worm cocoon).Animal-derivative fiber can derived from the feather of birds.Mineral-derivative natural fiber derives from mineral substance.Mineral-derivative fiber can derived from asbestos.Mineral-derivative fiber can be glass or ceramic fiber, such as, and microglass fiber, silica fiber, aluminum oxide, silicon carbide, norbide etc.

Can advantageously select or form fiber, they be degraded under specific pH or temperature, or degrades along with the time, and/or with the specific support fluid transported for propping agent, there is chemical compatibility.The fiber of useful synthesis is by such as can the solid cyclic dimer of or adjustable Water Under solution specific in known pH, temperature, time etc. or organic acid solid polymer making.Advantageously, under predetermined circumstances, the location resolution that fiber can be transported to.Advantageously, the decomposition of fiber can obtain the degradation production of environmental protection.

Embodiment

Material

30/70 sieve mesh pressure break sand

30/50 sieve mesh pressure break sand

40/70 sieve mesh pressure break sand

Diallyl dimethyl ammoniumchloride (Aldrich, St.Louis, MO)

LPEI 500 (polymer chemistry Creative Company, (Polymer Chemistry Innovations), Tucson, AZ)

Ethanol, 200 Proof (Aldrich, St.Louis, MO)

Hexane (VWR, Radnor, PA)

·FLOPAM EM533(SNF)

Polyethyleneglycol diglycidylether (Aldrich, St.Louis, MO)

Oxalic dialdehyde, 40 % by weight solution (Aldrich, St.Louis, MO)

HFC-44 (polymkeric substance joint venture (Polymer Ventures), Charleston, SC)

Sodium carboxymethyl-cellulose (Sigma-Aldrich, St.Louis, MO)

Ammonium persulphate (Sigma-Aldrich, St.Louis, MO)

The lauryl alcohol tensio-active agent (Ethal LA-12/80%) (Ethox Chemical Co, SC) of ethoxylation

Glycerine (US Glycerin, Kalamazoo, MI)

Repone K (Morton Salt, Chicago, IL)

Aerosil (Cabot, Boston, MA)

embodiment 1: prepare interpolymer layer

By adding 200g 30/70 sieve mesh pressure break sand in the tank to FlackTek Max 100 length, sand sample is prepared the interpolymer layer of 100ppm concentration.85g tap water and 2g 1% diallyl dimethyl ammoniumchloride (PDAC) solution is added in sand.Sample is manually vibrated about 5 minutes subsequently, vacuum filtration, and dry in the baking oven of 80 DEG C.Sand sample is removed subsequently and for test subsequently from baking oven.

Use method identical as mentioned above to prepare 10ppm interpolymer layer coating, difference is the PDAC solution only using 0.2g 1%.

Under maximum polymkeric substance load (" Max PDAC "), use method identical as mentioned above to prepare interpolymer layer, difference is to use 1g 20 % by weight PDAC solution.After process, the excessive tap water of sand, vacuum filtration, and dry in the baking oven of 80 DEG C.Sand sample is removed subsequently and for test subsequently from baking oven.

embodiment 2: prepare interpolymer layer

By dissolving 0.2g LPEI 500 in 10g ethanol, to form the ethanolic soln of 2% LPEI 500, thus on sand sample, prepare the interpolymer layer of 100ppm concentration.In 250mL round-bottomed flask, in 70g ethanol, add 0.75g 2% LPEI 500 solution.Subsequently 150g 30/70 sieve mesh pressure break sand is joined in round-bottomed flask.Use 65 DEG C of water-baths and use rotatory evaporator to remove desolventizing.Subsequently from flask removing sample and for test subsequently.

embodiment 3: prepare outer polymer layer

By under different conditions, by sand and liquid Flopam EM533 mixed with polymers, outer polymer layer is put on sand sample.In a kind of coating method, add straight polymer product.In another kind of coating method, by with hexane dilution, extend polymer product.For hexane dilution, in 40mL vial, joined by 10g polymkeric substance in 10g hexane, eddy current mixes, until homogeneous.Subsequently in FlackTek Max 100 tank, polymkeric substance is joined in 30g 30/70 sieve mesh pressure break sand sample.Sample is placed about 25 seconds in FlackTek DAC 150 speed mixing machine (SpeedMixer) under 2600rpm.From speed mixing machine, remove sample, and in the baking oven of 80 DEG C dried overnight.

embodiment 4: the performance of outer polymer layer, sedimentation (settling) time

The performance of the sand sample prepared in the embodiment is above evaluated in sedimentation test.Before testing, all sand samples are screened by 25 mesh sieves.By adding 1g sand sample in 100mL graduated cylinder in 100mL tap water, obtain the settling time.Subsequently by graduated cylinder reversion about 8 times, record all sands subsequently and be deposited in the time required bottom graduated cylinder.For each sample record three times.Settling time announces in Table 1.

Table 1 settling time

embodiment 5: the performance of outer polymer layer, the bed height of sedimentation

By observing the bed height of sedimentation in water, also can the sand sample with outer polymer layer of preparation in Evaluation operation example 3.In 20mL vial, in 10g tap water, add 1g sand sample.By bottle reversion about 10 times, with abundant moistening sand handled thing.Keep leaving standstill about 30 minutes with relief bottle.Digital calipers is subsequently for recording the height of sand bed in the vial.Result is announced in table 2.

The bed height of table 2 sedimentation

embodiment 6: the ionomer of outer polymer layer

By adding 1.3g Flopam EM533 polymkeric substance in FlackTek Max 100 tank in 40g sand, and outer polymer layer process 40g 30/70 sieve mesh pressure break sand sample tank manually being vibrated 2 minutes and formed.Sand is subsequently by 25 mesh sieve screenings.In order to evaluate the delay of the polymkeric substance on sand under shear, by 300mL glass beaker, in the 200g tap water with different PDAC level, adding the treated sand of 10g, test.Believe that PDAC will by ionic interaction, with stable polymerization nitride layer on sand.Use the top mixing machine with flat thruster type hybrid blade subsequently, slurry is stirred 5 minutes under 900rpm.Stop mixing subsequently, allow sample sedimentation 10 minutes.Use the Brookfield DV-III+ rheometer with LV-II rotor subsequently, measure the viscosity of supernatant liquor at 60 rpm.Use digital calipers also can be recorded in the bed height of the sand of sedimentation in beaker.Result is announced in table 3.

Table 3 polymer retention

Sample	PDAC circular cone, (ppm)	Viscosity (cP)	Bed height (mm)
				12	0	25	4.5
13	60	10	8.6
				14	200	2.5	6.3

embodiment 7: the covalent cross-linking of outer polymer layer-PEGDGE

By adding 0.66g polymkeric substance in FlackTek Max 100 tank in 20g sand, and manually vibrating 2 minutes, making four 30/70 sieve mesh pressure break sand samples by Flopam EM533 process.Subsequently the deionized water solution of the 1% new polyethyleneglycol diglycidylether of difference amount is joined in treated sand sample.Sample is manually vibrated 2 minutes again, places 1 hour in the baking oven of 100 DEG C subsequently.Subsequently from baking oven removing sample, and by 25 mesh sieve screenings.The bed height of following measurement four samples: by adding 1g sand sample in 20mL vial in 10g tap water, by bottle reversion about 10 times, with abundant moistening sand, and allows bottle keep leaving standstill about 10 minutes.Digital calipers is used to measure bed height subsequently.Result is recited in table 4.

The outer polymer layer of table 4 PEGDGE process

Sample	1％PEGDGE(g)	Bed height (mm)
			15	0.1	9.3
16	0.2	8.8
			17	1.0	6.2
18	0	12.7

embodiment 8: outer polymer layer-oxalic dialdehyde covalent cross-linking

By adding 0.66g polymkeric substance in FlackTek Max 100 tank in 20g sand, and manually vibrating 2 minutes, making four 30/70 sieve mesh pressure break sand samples by Flopam EM533 process.By adding 0.25g 40 % by weight oxalic dialdehyde in 20mL vial, and with alcohol dilution to 10g, prepare 1% oxalic dialdehyde ethanolic soln.Subsequently 1% glyoxal solution of difference amount is joined in treated sand sample, sample is manually vibrated 2 minutes, and place 30 minutes in the baking oven of 100 DEG C.From baking oven removing sand sample, and by 25 mesh sieve screenings.Bed height for sedimentation is measured, and in 20mL bottle, in 10g tap water, adds 1g sand, reverses about 10 times, keeps leaving standstill about 10 minutes with sedimentation.Digital calipers is used to measure bed height.Result is recited in table 5.

The outer polymer layer of table 5 oxalic dialdehyde process

Sample	1% oxalic dialdehyde (g)	Bed height (mm)
			19	0.2	3.8
20	0.5	3.5
			21	1.0	2.7
22	2.0	2.7

embodiment 9: anionic/cationic polymer treatment thing

In FlackTek Max 100 tank, the Polymer Ventures HCF-44 process of three 30g 30/70 sieve mesh pressure break sand samples.Tank is manually vibrated 2 minutes.Subsequently Flopam EM533 is joined in each sample.Tank is manually vibrated 2 minutes again.Sample is dried overnight at 80 DEG C subsequently.From baking oven removing sand sample, and by 25 mesh sieve screenings.Bed height for sedimentation is measured, and in 20mL bottle, in 10g tap water, adds 1g sand, reverses about 10 times, keeps leaving standstill about 10 minutes with sedimentation.Digital calipers is used to measure bed height.Result provides in table 6.

Table 6 anionic/cationic polymer treatment thing

Sample	HCF-44(g)	Flopam EM533(g)	Bed height (mm)
				23	0	0.45	10.26
24	0.07	0.38	8.08
				25	1.0	0.35	5.08
26	1.5	0.30	3.94

embodiment 10: the sand being coated with macromolecular particle

30g 30/70 sieve mesh pressure break sand sample is added in FlackTek Max 100 tank.0.3g paraffin is added in sand.Sample is placed in FlackTek DAC 150 speed mixing machine, and mixes 2 minutes under 2500rpm.After mixing, in sample, add 1g carboxymethyl cellulose.Sample is placed on again in FlackTek DAC 150 speed mixing machine, and mixes 1 minute under 2500rpm.Sand sample is by 25 mesh sieve screenings.Bed height for sedimentation is measured, and in 20mL bottle, in 10g tap water, adds 1g sand, reverses about 10 times, keeps leaving standstill about 10 minutes with sedimentation.Sand in this sample condenses in together immediately, and does not disperse in water, accurately can not measure bed height.

embodiment 11: modification sand beaker is tested

30g 30/70 sieve mesh pressure break sand sample is added in FlackTek Max 100 tank.By adding 0.45g polymkeric substance in tank, and manually vibrating 2 minutes, making sand Flopam EM533 process.Subsequently by sample dried overnight at 80 DEG C.After drying, from baking oven removing sample, and through 25 mesh sieve screenings.After screening, by 20mL bottle, add the treated sand of 1g to 10g tap water, prepare four samples.By bottle reversion about 10 times, and standing sedimentation 10 minutes.By adding 2g ammonium persulphate in 18g tap water, prepare 10% ammonium persulfate solution.Subsequently to 10% ammonium persulfate solution adding different amount in sample flasket.Sample is reversed several times with mixing, place 1 hour in the baking oven of 80 DEG C subsequently.After 1 hour, removing sample, and observe the bed height of sedimentation.Table 7 shows result.

Table 7 beaker is tested

Sample	10％APS(μL)	Sand suspends
			27	0	Suspend
28	180	Sedimentation
			29	90	Sedimentation
30	18	Sedimentation

embodiment 12: emulsion additive

In order to measure the impact of emulsion additive on certainly-suspended prop (" SSP ") performance, before coating propping agent sand, in emulsion polymer EM533, add glycerine and Ethal LA-12/80%.Following preparation three different polymer samples:

SSP polymkeric substance: 10g EM533, additive-free

SSP+ glycerine: 9g EM533 and 1g glycerine

SSP+ glycerine+Ethal:9g EM533+0.9g glycerine+0.1g Ethal LA-12/80%.

Each above-mentioned sample eddy current is mixed 30 seconds, to guarantee homogeneity.In order to prepare modification propping agent, the one in 50g 40/70 sand and more than 1.5g polymer samples being combined, mixing 30 seconds subsequently.The shear stability of modification propping agent sample is evaluated in 1 liter of shearing test.This test is included in square plastic beaker and adds 50g modification propping agent in 1 premium on currency, then on blade/tank mixing machine (EC Engineering, model C LM-4) with 200rpm (corresponding to about 550s ^-1shearing rate) mix different time quantums.Subsequently the sample of shearing is poured in 1000mL graduated cylinder, and pass through gravity settling 10 minutes, record the bed height of the propping agent sand of sedimentation subsequently.In order to compare, after the mixing of any amount, unmodified propping agent sand will produce the bed height of 10mm.Due to hydrogel layer encapsulating sand particles, relative to unmodified propping agent, certainly-suspended prop sample will produce higher height of bed journey (bed level).Usually, because hydrogel layer is from the result of the surface desorption of modification propping agent, improve the reduction that shearing rate or time can cause the bed height from-suspended prop.For this reason, bed height in this test is desirably in high as far as possible, especially after shearing.Following result display, adds the shear stability that glycerine improves bed height and product.Add glycerine and Ethal, although improve initial bed height, long-term shear stability reduces a little.These results are in figure 6 with figure explanation.

embodiment 13: glycerine and processibility

This experiment is sought to measure glycerine and the impact of other additive on certainly-suspended prop (representing with SSP below) performance.40/70 sand of 1kg drying is added in the rotating cylinder of the desk-top mixing machine of KitchenAid of the model KSM90WH of installation blade connection.3.09g glycerine is mixed with 27.84g EM533 emulsion polymer, subsequently mixture is joined the top of sand, and soak 1 minute.The time 0 time, start mixing machine with speed 1 (the elementary rotation of 72rpm).With 1-2 minute interval collection sample, and at 90 DEG C dry 1 hour.Subsequently, each sample experiences 1 liter of shearing test, wherein, adds the SSP of 50g in 1L water, and at 200rpm (about 550s ^-1shearing rate) down cut 20 minutes.1 rising amount cylinder is transferred to and sedimentation after 10 minutes, record bed height at Jiang Shui/SSP mixture.Only in 1kg sand, add separately 30.93g EM533 emulsion polymer to repeat this experiment.These results are shown in Fig. 7.As shown in the drawings, glycerine additive significantly improves bed height.

When repeating this experiment under higher mixing velocity, performance difference is even more remarkable.Now mixing machine is set as speed 4 (the elementary rotation of 150rpm).Under low mixing time, sample does not fully mix, and causes the incomplete coating of sand during shearing test and polymkeric substance easily from the surface desorption of SSP.Along with the raising of the mixing time of coating procedure, performance also improves, until reach desirable coating, obtains the maximum bed height of this sample.Subsequently, under higher mixing time, can see the bed height of go from bad to worse (reduction), may be the result of coating abrasion between the mixing period extended.Under higher mixing velocity, this process occurs even quickly, makes to be less than 1 minute for the process window of emulsion polymer separately.Along with adding and the use of lower mixing velocity of glycerine, this process window was widened to close to 15 minutes.Compared with the test being used alone emulsion polymer, glycerine causes process window to broaden, and shows that the SSP prepared product with glycerine is more sane.Meanwhile, glycerine allows polymer emulsion to reverse more completely, causes the bed height of better coating and raising.Under higher mixing velocity, the result using the test of the combination of glycerine and emulsion polymer EM533 to obtain is shown in Figure 8.

embodiment 14: the modification propping agent with anti-hard caking agent

Use and do not use anti-hard caking agent to prepare modification propping agent sample for comparing.For sample A, in FlackTek tank, add 50g 40/70 sand, in sand, add 1.5g EM533 emulsion polymer, and by this sample mix 30 seconds.After mixing, in sample, add 0.25g Calucium Silicate powder, and sample is mixed 30 seconds again.Subsequently by sample at 85 DEG C dry 1 hour.After drying, sample to be poured on above 25 mesh sieves and slight vibration 30 seconds.Measure the amount of the sand by sieve subsequently.For sample B, in FlackTek tank, add 50g 40/70 sand, in sand, add 1.5g EM533 emulsion polymer, and by sample mix 30 seconds.Subsequently by sample at 85 DEG C dry 1 hour.After drying, sample to be poured on above 25 mesh sieves and slight vibration 30 seconds.Measure the amount of the sand by sieve subsequently.Table 8 shows result.

Table 8

Sample	Sample total mass, g	By the quality of sieve, g	% is by sieve
				Sample A	50.5	50.16	99.3％
Sample B	50.5	15.71	31.1％

The result display of sieve test, it is effective for mixing the handling property of anti-hard caking agent to raising modification propping agent.

Sample A and B is joined respectively in 1L water, in EC Engineering mixing machine, shear 20 minutes at 200 rpm subsequently.After shearing, sample to be transferred in 1L graduated cylinder and standing sedimentation 10 minutes.After sedimentation, measure bed height, owing to mixing the result of anti-hard caking agent, display shear stability is not significantly lost.Table 9 shows these results.

Table 9

Sample	Bed height, mm
		Sample A	56.21
Sample B	59.67

embodiment 15: by dissolved water soluble polymer in monomer formulation then polymerization single polymerization monomer obtain sand hydrogel coating

Be that the mixture of the vinylformic acid (Aldrich 147230) of 0.5/0.4/0.1, polyethylene glycol monomethyl ether acrylate (Aldrich 454990) and polyethylene glycol dimethacrylate (Aldrich 437441) mixes with 7.5g polyoxyethylene glycol (Aldrich 202371) and the ammonium persulphate of 1 % by weight by 2.5g molar ratio.Gained solution mixes under a nitrogen with 100g 30/70 sieve mesh sand, raised temperature to 70 DEG C reaction 5 hours.Then use methanol wash gained solid, vacuum filtration is also dry in 80 DEG C of baking ovens.

embodiment 16: the polyurethane hydrogel coating of sand

100g 30/70 sieve mesh pressure break sand to be joined in Hobart type mixing machine and to be heated to 120 DEG C.Then add 6g polyoxyethylene glycol (Fluka 81190) and make mixing 1 minute.Then the Desmodur N75 of 0.53g Bayer company is added.Mix after more than 1 minute, add Isosorbide-5-Nitrae-two nitrine dicyclo [2.2.2] octane (Isosorbide-5-Nitrae-Diazabicyclo [2.2.2] octane, Aldrich D27802) catalyzer, make mixture reaction more than 5 minutes.With methanol wash gained solid, vacuum filtration is also dry in 80 DEG C of baking ovens.

embodiment 17: shear stability is tested

The shear stability of test sand sample of the coating of preparation in embodiment 15 and 16.1L tap water is added to 1L horizontal scale in the beaker of the square 1.25L of having capacity.Subsequently beaker is placed in EC Engineering CLM4 paddle mixer.Mixing machine is set as mixing at 300 rpm.Once mixing starts, in beaker, add the sand sample of 50g coating.After mixing 30 seconds at 300 rpm, mixing is reduced to 200rpm, and continues 20 minutes.At the end of this mixing, mixture is poured in 1L graduated cylinder, and allow sedimentation.After 10 minutes, the bed height of record sedimentation, as shown in table 10.Higher bed height shows good propping agent performance.

Table 10

Sand sample	Bed height after shearing, mm
		Undressed 40/70 sand	13.24
Embodiment 2	70.4
		Embodiment 3	57.64

embodiment 18: salt solution tolerates

Two 20mL bottles are equipped with 10mL tap water.Respectively, another two 20mL bottles are equipped with 10mL 1% KCl solution.To there being in the bottle of tap water the sand adding preparation in 1g embodiment 15, and to there being in the bottle of 1%KCl the sand adding preparation in 1g embodiment 15.In addition, to there being in the bottle of tap water the sand adding in 1g embodiment 6 preparation, and to containing adding the sand prepared in 1g embodiment 6 in the bottle of 1%KCl.By all four bottles reversions about 7 times, standing sedimentation 10 minutes subsequently.After sedimentation, measure bed height.Result is shown in table 11.

Table 11

Sand sample

Tap water bed height, mm

1%KCl bed height, mm

Embodiment 2	10.39	5.02
			Embodiment 6	17.15	9.23

embodiment 19: wear testing

Three 250mL beakers are equipped with 50mL tap water.The aluminium dish that a quality is about 5.5-6g is placed in each beaker.2 inch stirring bar are also placed in each beaker.All three beakers are placed on their magnetic agitation plate, and this plate is set as speed 5 grades.6g 40/70 sand is added in a beaker.The sand of preparation in 6g embodiment 15 is placed in second beaker.Sand is not added in 3rd beaker.Make each jar agitation 2 hours.After stirring, removing aluminium dish, washing, subsequent drying.Measurement quality again subsequently.The result being shown in table 12 shows, compared with unmodified sand, when contacting, and the wearing and tearing that in embodiment 15, the sand of preparation causes metallic surface less.

Table 12

	Initial mass, g	Quality after 2 hours, g	Total losses, g	% loses
					There is no sand	5.62	5.612	0.008	0.14％
40/70 sand, uncoated	6.044	6.027	0.017	0.28％
					Embodiment 15 sand	5.673	5.671	0.002	0.04％

embodiment 20: glycerine is on the impact of mixing

40/70 sand of 1kg drying is added in the rotating cylinder of the desk-top mixing machine of KitchenAid of the model KSM90WH of installation blade connection.Mixed with 27.84g emulsion polymer by 3.09g glycerine, the top subsequently to sand adds mixture, and soaks 1 minute.The time 0 time, start mixing machine with speed 4 (the elementary rotation of 150rpm).With 1-2 minute interval collection sample, and at 90 DEG C dry sample 1 hour.Subsequently, each sample experience shearing test, wherein, adds 50g SSP in 1L water, and at 550s ^-1down cut 20 minutes.Sedimentation, after 10 minutes, records bed height.The result of these shearing tests is shown in Fig. 9.This figure proves that both undermixing and overmixing all can affect the behavior of the propping agent of coating, causes polymkeric substance during shearing test to dissociate from sand.In this embodiment, the preferred amounts of mixing is about 5-20 minute.The impact of mixed duration on performance shows, coating is frangible when wetting, and once be dried, then more durable.Compared with testing with the coating being used alone emulsion polymer, the coating with the emulsion of blended glycerine seems to cause process window (that is, the acceptable amount of mixing time) to widen.In addition, the emulsion coating of blended glycerine seems more fully to reverse, and causes better coating performance, the bed height such as improved.

embodiment 21: use pugging mill to produce certainly-suspended prop

3 cubic feet of pugging mill type hybrid machines for the preparation of a collection of from-suspended prop.The 40/70 sieve mesh sand of about 50lbs is added in pugging mill.In 1L beaker, add about 756g SNF Flopam EM533, and 84g glycerine is mixed in polymkeric substance.Subsequently in pugging mill, evenly pour whole mixture at the top of sand.Pugging mill is opened, and mixes under about 70rpm.After mixing carries out 30 seconds, 60 seconds, 120 seconds, 180 seconds, 240 seconds, 300 seconds, 420 seconds and 600 seconds, take out sample.By sample drying 1 hour.After drying, in 1L water, add each sample of 50g, and mix 20 minutes at 200 rpm in EC Engineering CLM4.After mixing, sample is poured in 1L graduated cylinder, and sedimentation 10 minutes.After sedimentation, measure bed height.Result is shown in table 13.

Table 13

Pugging mill mixing time (second)	Bed height, mm
		30	29.34
60	23.49
		120	48.9
180	57.58
		240	55.71
300	44.88
		420	57.21
600	57.25

embodiment 22: deterioration with moisture (Wet aging)

Adopt the mode identical with embodiment 15 manufacture 400g oneself-suspended prop (SSP) sample.400g SSP be divided into 50g sample and be placed in closed container, and remaining on room temperature.After drying by various time quantum, the mode identical with embodiment 21 is adopted to test sample.Result is shown in table 14.

Table 14

Digestion time, hour	Final bed height, mm
		0	10.1
2	26.63
		4	60.16

embodiment 23:SSP adds uncoated propping agent

10mL tap water is added in 20mL bottle.Subsequently to adding propping agent sand in bottle, no matter be the SSP and unmodified 40/70 prepared according to embodiment 15.Reverse bottle several times, sedimentation subsequently 10 minutes.After sedimentation, measure bed height.Result is shown in table 15.

Table 15

SSP，g	40/70 sand, g	The bed height of sedimentation, mm
			0.5	0.5	5.46
0.75	0.25	5.71
			0.9	0.1	8.23

Embodiment 24: add anti-hard caking agent in SSP

Adopt and produce 400g SSP batch of material with the identical mode described in embodiment 15.Sample is divided into about 50g sub-sample, and in each sample, mixes the aerosil that 0.25g aggregate size is 80nm subsequently.Subsequently sample is applied, and at room temperature aging.Adopt and test sample with the identical mode described in embodiment 21.Result is shown in table 16.

Table 16

Hour, aging	The bed height of sedimentation, mm
		18	57.3
24	41.28
		42	44.29
48	44.76
		72	45.48

embodiment 25: the dust that can suck

Use 140 mesh sieves screening 200g uncoated and sand (40/70 sieve mesh) sample of hydrogel-coating prepared according to embodiment 15, collect the fine particle by 140 mesh sieves, and weigh.Relative to uncoated sand sample, the sample of the coating of sand proves that fine grain amount reduces by 86%.Result is shown in table 17.

Table 17

	The weight of sample	The weight of dust	The percent of total of dust
				Uncoated sample	200.011g	0.0779g	0.03895％
The sample of coating	200.005g	0.0108g	0.00540％

embodiment 26: the anti-hard caking agent with different-grain diameter

Operating speed mixing machine, at 800 rpm, mixes 30 seconds by 50g 40/70 sieve mesh sand with 2g SNF Flopam EM533.Add 0.625g anti-hard caking agent subsequently, material is again mixed 30 seconds in speed mixing machine.Allow sample leave standstill 3 hours, tested in shearing test at 20 minutes subsequently, allow sedimentation 10 minutes, and measure bed height.Result is shown in table 18.After the particle diameter shearing test using wide region, anti-hard caking agent can improve bed height.

Table 18

Anti-hard caking agent	Particle diameter	Bed height (mm)
			Talcum (Magnesium Silicate q-agent)	12 microns	16.76
Calucium Silicate powder	1-3 micron	39.78
			Aerosil	80 nanometers	73.87

embodiment 27: the chemical constitution of anti-hard caking agent

The various anti-hard caking agents of test are listed in table 19.For the reagent of each test, under speed 1 (144rpm), 700g 40/70 sand is mixed with 10% glycerine of 21.65g/90%EM533 mixture in KitchenAid mixing machine.Isolate 50g sample, and mix with appropriate anti-hard caking agent in speed mixing machine.In shearing test, test three samples mixed with 1% Calucium Silicate powder, 1.5% diatomite and 1.5% kaolin respectively immediately, and by other 7 samples with containing anti-hard caking agent contrast sample together with in 80 DEG C of baking ovens dry 1 hour.The mode identical with embodiment 17 is all adopted to test sample.Table 19-A display is applied with the wet bed height of (non-dry) sample after shearing test of anti-hard caking agent.Table 19-B display is applied with the bed height of (at 80 DEG C 1 hour) sample after shearing test of the drying of anti-hard caking agent.

Table 19-A

Anti-hard caking agent	Amount	Bed height (mm)
			Calucium Silicate powder	0.5g(1％)	30.26
Diatomite (DE)	0.75g(1.5％)	12.95
			Kaolin clay	0.75g(1.5％)	18.46

Table 19-B

embodiment 28: anti-hard caking agent: the amount needed for drying

In little plastics pot, add seven 50g 40/70 sand samples, in each tank, then add each 10% glycerine/90% emulsion polymer mixture of 2g.After speed mixes 30 seconds, in seven samples, add 0.25g, 0.375g, 0.5g, 0.675g, 0.75g, 1g and 2.5g Calucium Silicate powder powder, sand is mixed 30 seconds again.Without the need to further drying step, sample is carried out shearing test, and record the bed height (in mm) of sedimentation.Result is shown in Figure 10.Silicon-dioxide is used to carry out similar experiment as anti-hard caking agent.The sand that these test displays are coated with hydrogel can use anti-hard caking agent process, the product of acceptable bed height after can being produced shearing test not need independent drying step.

embodiment 29: silicon-dioxide anti-hard caking agent

In canister, add 50g 40/70 sand, then add the 10% glycerine/90%EM533 of 2g.By tank at 800 rpm speed mix 30 seconds, add appropriate aerosil subsequently, as described in table 20, by its remix 30 seconds.Sample experiences 20 minutes shearing tests, and records bed height.Do not use oven drying.Result is shown in table 20.

Table 20

The batch of material of the sand of coating is mixed in KitchenAid mixing machine, and is separated into several 50g samples.Subsequently to 3 samples each in add the aerosil of the various size of 1 % by weight, mixing, and shearing test.These test results are shown in table 21.

Table 21

Powder	Approximate size	The amount added	Bed height
				Aldrich aerosil	7nm	1％	48.86mm
Aldrich silica nano-powders	10nm	1％	35.48mm
				Cabot EH-5	80nm aggregate	1％	59.10mm

embodiment 30: preheating sand

500g 30/50 sand is placed 1 hour in 90 DEG C of baking ovens, stirs once in a while, until the temperature equilibrium of sand.Sand mixes subsequently in the planetary-type mixer be purchased, until it reaches the preheating temperature (45 DEG C, 60 DEG C or 80 DEG C) of expectation, now adds 20.8g SNF Flopam EM533, and by sample mix 7 minutes.Subsequently batch of material is separated, and in the baking oven of 80 DEG C the dry regular hour.For the sample of non-preheating, 500g 30/50 sand is placed in mixing machine rotating cylinder together with 20.8g polymer emulsion, mixes 7 minutes, the time quantum that subsequent drying is different.Use standard program shearing test all samples: in 1000g tap water, add 50g sand, with 550s ^-1shearing rate stir 20 minutes, sedimentation 10 minutes in 1L graduated cylinder subsequently.Result is shown in Figure 11.These results show, it is acceptable for sand being preheated to 45 DEG C, but 60-80 DEG C can cause bed height lower in shearing test.

Real execute example 31: force dry air

Operating speed mixing machine, mixes 30 seconds by 50g 40/70 sand with 4% emulsion polymer (2g) prepared according to embodiment 14.Sample is transferred in the container being equipped with the hot air gun being set in 90 DEG C, 95 DEG C or 100 DEG C.Allow sample in heating gun, keep totally 30 minutes, when 5 minutes, 10 minutes, 15 minutes and 30 minutes marks, take out 5g sample.These samples use little shearing test to test subsequently, carry out as follows: 2 inch stirring bar that 100mL tap water rotates under being set as being used in 500rpm in 300mL beaker stir; In beaker, add 5g sand sample, and shear 3 minutes; Whole solution is transferred to 100mL graduated cylinder, reverses once, sedimentation 5 minutes, and measure bed height.The result of these tests is shown in Figure 12.As shown in figure, the higher temperature of the pressure air entered causes drier and better bed height.To the susceptibility sheared, seven forks are harrowed (prong rake) by pulling before and after sample, to simulate slight shearing when drying to test the SSP when using pressure dry air.Prepare two 50g SSP batch of materials, and under 110 DEG C of air dry 30 minutes.First is completely static, and second constant raking during 30 minute time of drying.Use large shearing test to test two samples 20 minutes, the settling time is 10 minutes.Static dry sample obtains the bed volume of the sedimentation of 100.63mm; And use the slight sample shearing drying to obtain the bed volume of the sedimentation of 109.49mm.

embodiment 32: use vertical screw (vertical screw) mixing

Structure is vertical screw blender on a small scale.Sand and SNF Flopam EM533 is added, the screw mixes rotated under being subsequently used in about 120rpm in container.Sample is divided into two 50g parts subsequently, one dry in 80 DEG C of baking ovens, and another mixes with 0.5g (l % by weight) aerosil.The two all experiences the shearing test as described in embodiment 17 subsequently.The result that bed height is measured is as follows: oven drying 1 hour, obtains the bed height of 101.34mm; Undried, wherein add the 7nm aerosil of 1%, obtain the bed height of 91.47mm.Not only oven drying but also add anti-hard caking agent desciccate and obtain high bed height.

embodiment 33: microwave drying

In little plastics pot, add 50g 40/70 sand, the blend subsequently in speed mixing machine, containing with 2g (10% glycerine/90% emulsion polymer) at 800 rpm mixes 30 seconds.Sample is placed in 700W microwave oven, and high fire heats 45 seconds.By sample screening and cooling, subsequently in EC Engineering CLM4 mixing machine, shear 20 minutes at 200 rpm.After mixing, sample is transferred in 1L beaker, and sedimentation 10 minutes.After sedimentation, measure bed height (in millimeter), obtain the bed height of 52.43mm.Microwave heating obtains having the acceptable bed height of relatively short time of drying.

embodiment 34: mix with anti-hard caking agent and heat

In KitchenAid mixing machine, 500g 40/70 sand is mixed 8 minutes with 20g (20% glycerine/80% emulsion).Then add 0.44% Cabot EH-5 aerosil, and mix 2 minutes, sample uses heating gun heating subsequently.Under 13,18,24 and 26 minutes mixing times, collect 50g sample.These sample shear are tested 20 minutes, and records bed height.Result is shown in Figure 13.The combination of glycerine and silicon-dioxide makes process window longer.

embodiment 35: microwave drying

400g 30/50 sand and 16g (4% weight) emulsion polymer prepared according to embodiment 14 are combined, and mix 7 minutes in the desk-top mixing machine of KitchenAid.Use the dry 50g sample of baking oven (80 DEG C), and other 7 samples are placed 5,10,20,30,45,60 and 120 seconds respectively in 700W microwave oven.Shearing test (20 minutes long) as described in embodiment 12 is carried out and loss (LOI) test of lighting a fire to sample.LOI test comprises and add 10g sand in the crucible of taring, it is placed 1 hour in 960 DEG C of baking ovens.Heat after 1 hour, crucible is cooled 1 hour in moisture eliminator, weighs subsequently.Time of drying, bed height and LOI show in table 22.Difference between initial weight and the final weight per-cent of total initial sand weight represents, as shown in figure 14.

Table 22

Drying means	Time of drying	Bed height (mm)	LOI(％)
				Baking oven	1 hour	41.36	1.8
Microwave	5 seconds	15.54	3.33
				Microwave	10 seconds	16.14
Microwave	20 seconds	24.68
				Microwave	30 seconds	39.99	2.929
Microwave	45 seconds	53.31
				Microwave	60 seconds	49.84
Microwave	120 seconds	57.81	2.279

These tests show, microwave drying technology is main except anhydrating from the sample of coating, instead of oil.

embodiment 36: vacuum-drying

250g 30/50 sand and 10g such as the emulsion polymer described in embodiment 14 are combined.Sand mixture is stirred 7 minutes in the desk-top mixing machine of KitchenAid under most jogging speed, is divided into 50g sample subsequently, and in vacuum drying oven, under 24 inches Hg vacuum, at 25 DEG C, 50 DEG C and 85 DEG C dry 1 hour, 1 hour and 30 minutes respectively.Sample is cooled to room temperature, screening, and shearing test (as described in embodiment 12) 20 minutes.Result is shown in table 23.

Table 23

Sample #	Temperature (DEG C)	Time	Bed height (mm)
				1	25	1 hour	16.79
2	50	1 hour	17.34
				3	85	30 minutes	18.04

At these test periods, there is no sample complete drying, can affect drier although other test can show higher temperature.

embodiment 37: the hydrogel coating being polymerized the sand obtained by Admicelle

250g 30/70 pressure break sand is joined 500ml degassed containing 0.6mM cetyl trimethylammonium bromide (CTAB) tensio-active agent (being equivalent to the micelle-forming concentration of 2/3CTAB) in advance, and the aqueous solution of 6mM monomer (mixture of the acrylic acid/acrylamide of mol ratio 30/70).25 DEG C of mild stirring 24 little carrying out at present, CTAB and monomer can be adsorbed in sand grains.Then, 0.6mM ammonium persulphate to be joined in reactor and within 3 hours, to be polymerized 80 DEG C of reactions.Sample drying with the water washing of some volumes, and can spend the night by excess polymeric and tensio-active agent in the vacuum drying oven of 80 DEG C.

embodiment 38: the hydrogel coating of the sand obtained by inverse suspension polymerization

60ml deionized water, 6.6g acrylamide, 3g vinylformic acid, 2.4g N, N'-methylene-bisacrylamide, 0.1g ammonium persulphate, 2.0g sodium-chlor and 2 N, N, N', N'-Tetramethyl Ethylene Diamines are joined in flask.200g 30/70 sieve mesh pressure break sand is added and under making whole mixture remain on the temperature of < 10 DEG C in this solution.200ml hexanaphthene is added and the whole mixture of vigorous stirring under a nitrogen in mixture.Then raised temperature to 60 DEG C carry out reaction in 6 hours.Filter the particle of the coating of synthesis and use hot water, washing with acetone, and dry at decompression 45 DEG C.

embodiment 39: coated polymeric

Mixture for applying propping agent can by combining 10g glycerine and 90g Flopam EM533 and using whirlpool mixing machine to mix 30 seconds and prepare in vial.This polymeric blends will use in the following embodiments.

the preparation from-suspended prop (" SSP ") of embodiment 40:40/70 sieve mesh

By 500g 40/70 pressure break sand being joined the SSP sample of 40/70 mesh size prepared in the rotating cylinder of KitchenAid mixing machine.Coated polymeric in 20g embodiment 39 is joined in sand.Mixing machine is adjusted to 1 grade, sand and polymeric blends are mixed 7 minutes.After mixing, sample at 85 DEG C dry 1 hour.After 1 hour, sample is removed from baking oven, and any caking is broken to single crystal grain.

the preparation from-suspended prop (" SSP ") of embodiment 41:30/50 sieve mesh

By 500g 30/50 pressure break sand being joined the SSP sample of 30/50 mesh size prepared in the rotating cylinder of KitchenAid mixing machine.Coated polymeric in 20g embodiment 39 is joined in sand.Mixing machine is adjusted to 1 grade, sand and polymeric blends are mixed 7 minutes.After mixing, sample at 85 DEG C dry 1 hour.After 1 hour, sample is removed from baking oven, and any caking is broken to single crystal grain.

embodiment 42: from-suspended prop (" the SSP ") level of fines to the minimizing of sand

Prepare one group of top with 40 sieve meshes, middle 70 sieve meshes and bottom with the standard mesh sieve of dish.Measure each clean/dry sieve tare weight amount record.40/70 sieve mesh SSP in 50g embodiment 20 joined the top of sieve group and manually shake storehouse 5 minutes.After shake, untie storehouse and each sieve is weighed.The Mass Calculation that each sieve retains is primary sample massfraction, and in dish, the amount of remaining sample represents fines mark, as by 70 sieve meshes sieves lower define.Unmodified 40/70 sieve mesh pressure break sand is replaced 40/70SSP, repeats this process.Result in table 24 shows the particle size distribution of 40/70 SSP.Table 25 comprises the grain size analysis of unmodified 40/70 pressure break sand.Result shows in 40/70 SSP, to reduce (1.2% to 4.8%) by the amount of the material of 70 sieve mesh sieves.This shows that SSP can containing the fines particle reduced than sand sample size.

Table 24 particle size distribution

40/70 SSP of sample: 49.516g

Sieve mesh	Tare weight, g	Remaining mass, g	The weight that sand retains, g	Distribution of sizes
					40	118.826	127.685	8.859	17.9％

70	111.136	151.036	39.9	80.6％
					Dish	81.501	82.072	0.571	1.2％
		Amount to	49.33	99.6％

The particle size distribution of unmodified 40/70 white sand of table 25

40/70 white sand of sample: 50.974g

Sieve mesh	Tare weight, g	Final weight, g	The weight that sand retains, g	Distribution of sizes
					40	118.806	118.921	0.115	0.2％
70	111.045	159.465	48.420	95.0％
					Dish	81.503	83.935	2.432	4.8％
		Amount to	50.967	100.0％

embodiment 43: friction reduces

1L tap water is joined in square beaker, and this beaker is placed in EC Engineering CLM-4 mixing machine.Open mixing machine and be set to 200rpm mixing velocity.30/50 SSP in 120g embodiment 21 is joined in tap water.This mud is mixed 20 minutes, is then transferred to 1L graduated cylinder and standing sedimentation 10 minutes.After sedimentation, collect supernatant liquor.Repeat this process until collect 2L supernatant liquor fluid.The friction using flow circuits device to measure the fluid collected subsequently reduces.It is that the pump of 55gph forms that described flow circuits is multiplied by 3 inches of (ft) stainless steel testing conduits and transmission constant flow rate by 0.12 foot (ID).Corresponding to these conditions of Reynolds quantity 23000, determine that fluid is in turbulent flow.Friction is reduced mark (%FR) and is determined by the experiment of the pressure being determined at the entrance and exit of testing conduit under constant flow speed.Following equalities calculates friction and reduces mark: %FR=100* (1-(Δ P _i/ Δ P ₀)), wherein, at this Δ P _ifor the Pressure Drop using SSP supernatant liquor fluid to cross over testing conduit, Δ P ₀for the Pressure Drop using tap water to cross over testing conduit.Force value is Δ P _i=11.8psi, Δ P ₀=38.5psi, the friction corresponding to 69% reduces (%FR).This shows that SSP contributes to significantly reducing the friction of associated fluid, represents the minimizing in pumping needs.

embodiment 44: hydraulic conductivity is tested

In order to make the hydraulic conductivity model of simulation propping agent packing layer, the SSP of 30/50 mesh size in 48g embodiment 21 mixes with 1 premium on currency.Add the ammonium persulphate of 0.1% level, and mixture is heated to 185 °F 1 hour.After cool to room temperature, by the pillar filtering mixt of bottom with 2.25 inches of ID of 100 sieve mesh sieves, separating particles from fluid.It is dark that this particle forms the bed of 0.5 inch on 100 sieve mesh sieves, and measured by run by gravity by the flow of the different fluid of bed.Compared with deriving bed with SSP, set up flat sand bed according to similar method and flow.Make in this way, the sand (25 seconds 250ml effluents) of flow (the 28 seconds 250ml effluents) peace obtained by SSP is almost identical, show SSP once with oxidation gel breaker such as ammonium persulphate process, injurious effects are not had to the hydraulic conductivity of the propping agent packing layer of sand bed or simulation.

embodiment 45: have anti-hard caking agent from-suspended prop (" SSP ")

Anti-hard caking agent is except can replacing drying step, and they can be used as the handling property usually improving SSP.Particulate materials different is in a large number tested as anti-hard caking agent, as following table 26.In order to prepare the sample of each material, 800g 30/50 sieve mesh sand mixes with the coated polymeric in 32g embodiment 19 in KitchenAid mixing machine under speed 1 (144rpm).Get 20g sample and blended in mixing machine with the anti-hard caking agent selected, anti-caking Rapid Dose Calculation is the percentage ratio of total sand in the sample to which.Observe the consistence of sample and be recorded as " outward appearance before drying ", then 85 DEG C of dryings 1 hour.Again observe their consistence and be recorded as " dried outward appearance ".Then sample is stood under 80%-90% relative humidity 25-35 DEG C condition 1 hour to evaluate their anti-caking character, and observe consistence and be recorded as " outward appearance after humidity exposure ".Result is as shown in table 26 below, shows that anti-hard caking agent improves the handling property of SSP, and wherein unrestricted flow is desired feature.

Table 26 adds the evaluation of the SSP sample having anti-hard caking agent

embodiment 46: the sand using the coating of SMA 4000i process resin

By the sand of 25g resin-coating being joined in 250mL round-bottomed flask the sand using SMA 4000i coated with resins to apply.Respectively, 0.25g SMA 4000i is dissolved to prepare 7% solution in 3.57g tetrahydrofuran (THF) (THF).Then, in round-bottomed flask, 1.43g THF solution is joined in the sand of resin-coating.Add in extra THF to round-bottomed flask until sand is recessed circle (coved).Then Rotary Evaporators is used to steam from sample except THF.

embodiment 47: the sand using the coating of SMA 4000i process resin

By the sand of 25g resin-coating being joined in 250mL round-bottomed flask the sand using SMA 4000i coated with resins to apply.Respectively, 0.25g SMA 2000i is dissolved to prepare 7% solution in 3.57g tetrahydrofuran (THF) (THF).Then, in round-bottomed flask, 0.72g THF solution is joined in the sand of resin-coating.Add in extra THF to round-bottomed flask until sand is recessed circle.Then Rotary Evaporators is used to steam from sample except THF.

embodiment 48: the sand using the coating of SMA 2000i process resin

By the sand of 25g resin-coating being joined in 250mL round-bottomed flask the sand using SMA 2000i coated with resins to apply.Respectively, 0.25gSMA 4000i is dissolved to prepare 7% solution in 3.57g tetrahydrofuran (THF) (THF).Then, in round-bottomed flask, 1.43g THF solution is joined in the sand of resin-coating.Add in extra THF to round-bottomed flask until sand is recessed circle.Then Rotary Evaporators is used to steam from sample except THF.

embodiment 49: the sand using the coating of SMA 2000i process resin

By the sand of 25g resin-coating being joined in 250mL round-bottomed flask the sand using SMA 2000i coated with resins to apply.Respectively, 0.25gSMA 2000i is dissolved to prepare 7% solution in 3.57g tetrahydrofuran (THF) (THF).Then, in round-bottomed flask, 0.72g THF solution is joined in the sand of resin-coating.Add in extra THF to round-bottomed flask until sand is recessed circle.Then Rotary Evaporators is used to steam from sample except THF.

embodiment 50: the sand using the coating of Pluronic L31 process resin

The sand of Pluronic tensio-active agent L31 coated with resins coating is used by the sand of 20g resin-coating being joined little FlackTek bottle.0.025g tensio-active agent is joined the sand of resin-coating.Then FlackTek speed mixing machine is used by sample to mix 30 seconds at 800rpm.

Embodiment 51: the sand using the coating of Pluronic L35 process resin

By the sand of 20g resin-coating being joined in little FlackTek tank the sand using Pluronic tensio-active agent L31 coated with resins to apply.0.025g tensio-active agent is joined in the sand of resin-coating.Then FlackTek speed mixing machine is used by sample to mix 30 seconds at 800 rpm.

embodiment 52: the sand using the coating of Pluronic L81 process resin

By the sand of 20g resin-coating being joined in little FlackTek tank the sand using Pluronic tensio-active agent L35 coated with resins to apply.0.025g tensio-active agent is joined in the sand of resin-coating.Then FlackTek speed mixing machine is used by sample to mix 30 seconds at 800 rpm.

embodiment 53: use the sand of 2HT-75 process resin coating

Use by the sand of 25g resin-coating is joined in 250mL round-bottomed flask the sand of 2HT-75 coated with resins coating.Respectively, by 0.25g 2HT-75 dissolves to prepare 7% solution in 3.57g Virahol (IPA).Then, in round-bottomed flask, 0.72g Virahol (IPA) solution is joined in the sand of resin-coating.Add in extra Virahol (IPA) to round-bottomed flask until sand is recessed circle.Then Rotary Evaporators is used to steam from sample except Virahol (IPA).

embodiment 54: use the sand of 464 process resin coatings

Use by the sand of 20g resin-coating is joined in little FlackTek tank the sand of 464 coated with resins coatings.By 0.025g 464 join in the sand of resin-coating.Then FlackTek speed mixing machine is used by sample to mix 30 seconds at 800 rpm.

embodiment 55: coated polymeric mixture

9g Flopam EM533 (SNF) is combined with 1g glycerine in 20mL bottle.Then this bottle is mixed 30 seconds in whirlpool mixing machine.

embodiment 56: the hydrogel coating of sand sample

20g embodiment 46 is placed in little FlackTek tank to sample prepared by embodiment 54 and prepares sand sample.Coating mix prepared by 0.6g embodiment 35 is joined in each tank.Then FlackTek speed mixing machine blend mixture 1 minute is at 800 rpm used.Then by this sample 100 DEG C of dryings 30 minutes.After drying, each for 1g sample is joined and is equipped with in the 20mL bottle of 10mL tap water.Mix bottle 1 minute gently, then standing sedimentation 10 minutes.After sedimentation, measure bed height to determine polymer hydration.The result of test is shown in table 27.

The bed height of table 27 sedimentation

embodiment 57: humidity aged test (metal-chelating linking agent)

Tyzor TE is trolamine titanium chelating (the triethanolamine titanium chelate) ethanolic soln of 80%.Tyzor TEAZ is the trolamine zirconium chelating product of 100% activity.These metallo-chelates are dispersed in Viscotrol C with different concns, and add in step at second of coating procedure and be applied on propping agent.The sample of propping agent of coating prepares by being joined in 100g 30/50 sieve mesh propping agent white sand by the blend of 3g Flopam EM533 and glycerine in FlackTek Max 100 tank.Then sample is mixed 30 seconds under 850rpm in FlackTek speed mixing machine.Then from speed mixing machine, shift out sample and use metallo-chelate/Viscotrol C blend process in some cases.Then send sample back to speed mixing machine and mix 30 seconds under 850rpm.Then from speed mixing machine, shift out sample, be transferred to watch-glass and force in air lab oven dry 30 minutes at 100 DEG C.After drying, by 18 sieve mesh sieve screening samples.In order to humidity aged, the sample prepared by 50g to be placed in Max 100FlackTek tank and to be placed in humidity chamber 1 hour.The relative humidity of this room remains between 60-70%.After moistening, sample uses 1000lbs load testing 30 seconds in Carver Press cell (2.25 " I.D.).The caking of sample can visually assess and with compare (without second time add).The scope of sample caking scoring can from 1 to 4, and " 1 " represents solid block and " 4 " represent unrestricted flow, non-agglomerated material.Result is shown in table 28.

Table 28 adds the caking result of metallo-chelate

Sample	Metallo-chelate	Metal-chelating substrate concentration (ppm)	Caking mark
				1	Nothing	0	1
2	Tyzor TE	600	3
				3	Tyzor TE	1500	3
4	Tyzor TEAZ	600	2
				5	Tyzor TEAZ	900	3

(the caking mark of table 14: can chip-proof solid block during " 1 "-process, during " 2 "-process, major part starts broken solid block, caking frangible during " 3 "-leave compressed element, " 4 "-formed without caking).

embodiment 58: humidity aged test (powder additive)

The sample of propping agent of coating prepares by being joined in 100g 30/50 sieve mesh propping agent white sand by the blend of 3g Flopam EM533 and glycerine in FlackTek Max 100 tank.Sample mixes 30 seconds under 850rpm in FlackTek speed mixing machine.Then from speed mixing machine, shift out sample and use dried powder process in some cases.Then send sample back to speed mixing machine and mix under 850rpm and be uniformly distributed in the sample to which to make powder for 30 seconds.Then from speed mixing machine, shift out sample, be transferred to watch-glass and force in air lab oven dry 30 minutes at 100 DEG C.After drying, by 18 sieve mesh sieve screening samples.In order to humidity aged, sample prepared by about 50g be placed in Max 100 FlackTek tank and be placed in humidity chamber 1 hour.The relative humidity of this room remains between 60-70%.After moistening, sample uses 1000lbs load testing 30 seconds in Carver Press cell (2.25 " I.D.).The caking of sample can visually assess and with compare (without second time add).The scope of sample caking scoring can from 1 to 4, and " 1 " represents solid block and " 4 " represent unrestricted flow, non-agglomerated material.Result is shown in table 29.

Table 29 has the caking result of the propping agent of the coating of powder additive

Sample	Powder	Its melting point (DEG C)	Powder concn (% by weight)	Caking mark
					6	Nothing	N/A	0.0％	1
7	Thixcin-R	85	0.5％	2
					8	Stearic acid	70	0.6％	3

(the caking mark of table 15: can chip-proof solid block during " 1 "-process, during " 2 "-process, major part starts broken solid block, caking frangible during " 3 "-leave compressed element, " 4 "-formed without caking).

embodiment 59: oil base additive

The material testing some oil bases or relative hydrophobic is to determine that they are reducing the effect in-suspended prop (SSP) damp sample caking.30/50 sand by the speed in KitchenAid mixing machine 1 time 300g being preheated to 45 DEG C mixes to prepare sample with 9g 10% glycerine/90%Flopam 533 mixture.Mix after 1 minute, introduce Second addition (usually accounting for 0.2% of sand quality) and blend mixture 1 minute.Use heating gun and KitchenAid by sample drying under moderate shearing condition.Then sample stands > 50%RH 1 hour in humidity chamber.Then their caking behavior is tested individually by compression verification.This comprises use Carver Press and compresses 30 seconds with 200PSI in the compression unit, then shifts out from unit and observes.Gained caking (reference table 16, compression verification) grade with following mark: can chip-proof solid block during " 1 "-process, during " 2 "-process, major part starts broken solid block, caking frangible during " 3 "-leave compressed element, " 4 "-formed, as table 30 without caking.

Table 30 has the anti-caking result of the propping agent of the coating of oil base additive

With the sample that Adogen 464 processes in this test, even if also almost do not form caking in very low amount.

Equivalent

Although disclosed specific embodiment of the invention scheme, be illustrated as illustrative and not restrictive above herein.Although preferred embodiment specifically show with reference to it and describe the present invention, it will be understood by those skilled in the art that not departing under the scope of the present invention that claims comprise, the various changes of form and details can be carried out.After reading this specification, many variants of the present invention it will be apparent to those skilled in the art that.Unless otherwise indicated, all numerals otherwise for this specification sheets and the expression reaction conditions of claims, the amount of composition etc. are interpreted as being modified by term " about " in all cases.Therefore, unless contrary situation is described, otherwise digital parameters described herein is approximation, and it can be sought the character of the expectation obtained according to the present invention and become.

Although the present invention portion shows using preferred embodiment is described, it should be understood that for those skilled in the art not departing under the scope of the present invention that claims comprise, the various changes of form and details can be carried out.

Claims (56)

1. a modification propping agent, described modification propping agent contains proppant particles and hydrogel coating, wherein, the surface of proppant particles localizes described hydrogel coating with production modification propping agent.

2. modification propping agent according to claim 1, wherein, described proppant particles contains sand.

3. modification propping agent according to claim 1, wherein, described proppant particles contains bauxite, sintered bauxite, pottery or low-density propping agent.

4. modification propping agent according to claim 1, wherein, described proppant particles contains the matrix of resin-coating.

5. modification propping agent according to claim 3, wherein, described modification propping agent is also containing adhesion promoter, and described hydrogel coating is fixed on the matrix of described resin-coating by described adhesion promoter.

6. modification propping agent according to claim 1, wherein, described hydrogel coating contains the polymkeric substance of water-swellable.

7. modification propping agent according to claim 6, wherein, the weight-average molecular weight of described polymkeric substance is >=about 1,000,000 g/mol, is preferably >=about 5,000,000 g/mol.

8. modification propping agent according to claim 1, wherein, it is free-pouring that described propping agent experiences after 1 hour when drying or at relative humidity 25-35 DEG C of about 80-90%.

9. modification propping agent according to claim 1, wherein, described propping agent is dry.

10. the modification propping agent according to claim 1 or 8, wherein, described hydrogel coating is durable.

11. modification propping agents according to claim 10, wherein, the shearing ratio being tested the propping agent determined by shear analysis is >=0.6.

12. modification propping agents according to claim 1, wherein, are applied on proppant particles also dry to form the film of basic continous on the surface at proppant particles with liquid coating preparation by described hydrogel coating.

13. according to the modification propping agent in the claims described in any one; wherein; described modification propping agent is manufactured by reversed-phase emulsion paint-on technique; wherein; described proppant particles matrix is combined with reversed-phase emulsion; wherein, oil phase forms the continuous print phase of emulsion and the solution of super absorbent polymer in water or suspension form phase that is discontinuous, emulsification.

14. modification propping agents according to claim 1, wherein, described hydrogel coating contains the polymkeric substance be selected from by the following group formed: the emulsion polymer of the multipolymer of the multipolymer of polyacrylamide, hydro-polyacrylamide polyacrylic acid, acrylamide and the unsaturated ionic comonomer of ethylenic, acrylamide and acrylate, poly-(vinylformic acid) or their salt, carboxymethyl cellulose, Natvosol, hydroxypropylcellulose, Gua Er, carboxymethyl guar, Carboxymethyl hydroxypropyl guar, hydrophobic association swellable and emulsion polymer.

15. modification propping agents according to claim 1, wherein, the hydration of described propping agent in excessive water stands the volumetric expansion of at least 100%, is preferably at least 500%.

16. modification propping agents according to claim 1, wherein, the amount of described hydrogel coating is less than about 5 % by weight of gross dry weight.

17. modification propping agents according to claim 1, wherein, described modification propping agent is also containing anionic/cationic polymkeric substance pair, and this anionic/cationic polymkeric substance is to containing cationic polymers and high molecular weight anionic polymer.

18. modification propping agents according to claim 17, wherein, described cationic polymers is selected from by the following group formed: poly-DADMAC, LPEI, BPEI, chitosan and cationic polyacrylamide.

19. modification propping agents according to claim 1, wherein, described modification propping agent is also containing oxidation gel breaker or enzyme breaker.

20. modification propping agents according to claim 19, wherein, described oxidation gel breaker is selected from by the following group formed: superoxide, Magnesium peroxide, calcium peroxide, persulphate, nitrate, bromate, ozone and oxychloride.

21. modification propping agents according to claim 19, wherein, described oxidation gel breaker is the cation-modified oxidation gel breaker that can be associated by ionization and hydrogel.

22. modification propping agents according to claim 19, wherein, described enzyme breaker is the positively charged ion enzyme breaker that can be associated by ionization and hydrogel.

23. modification propping agents according to claim 1, wherein, described modification propping agent is also containing hydrophobic skin.

24. modification propping agents according to claim 23, wherein, described hydrophobic skin is selected from by the following group formed: lipid acid, aliphatic amine, hydrophobic quaternary amine, aliphatic amide, winterized stearin, vegetables oil, Viscotrol C, triacetin, wax, polyethylene oxide and poly(propylene oxide).

25. modification propping agents according to claim 1, wherein, described modification propping agent is also containing the hydration additive postponed.

26. modification propping agents according to claim 25, wherein, the hydration additive of described delay is selected from by the following group formed: low hydrophile-lyophile balance tensio-active agent, the repellents getting rid of coating surface promoting agent, ion crosslinking agent, covalent crosslinking agent and monovalent salt charge shielding agent.

27. modification propping agents according to claim 1, wherein, described modification propping agent is also containing alcohol, and described alcohol is selected from by the following group formed: ethylene glycol, propylene glycol, glycerine, propyl alcohol and ethanol.

28. modification propping agents according to claim 1, wherein, described modification propping agent is also containing anti-hard caking agent.

29. modification propping agents according to claim 28, wherein, described anti-hard caking agent is selected from by the following group formed: hydrophobic layer material, fine particle material and linking agent.

30. modification propping agents according to claim 28, wherein, described anti-hard caking agent is selected from by the following group formed: Calucium Silicate powder, calcium carbonate, talcum, kaolin, wilkinite, diatomite, silicon-dioxide, colloid silica, Microcrystalline Cellulose and attapulgate.

31. modification propping agents according to claim 30, wherein, described anti-hard caking agent is selected from by the following group formed: aerosil, Calucium Silicate powder, calcium carbonate, kaolin, wilkinite and attapulgate.

32. modification propping agents according to claim 1, wherein, described hydrogel coating contains additive.

33. modification propping agents according to claim 32, wherein, described additive is chemical additive.

34. modification propping agents according to claim 32, wherein, described additive is tracer agent.

35. modification propping agents according to claim 1, wherein, described modification propping agent contains less fines than unmodified proppant particles.

36. 1 kinds of waterfrac treatment preparations, this waterfrac treatment preparation contains the modification propping agent in claim 1-35 described in any one and is oxidized gel breaker or enzyme breaker.

The method of 37. 1 kinds of fractured wells, described method comprises:

Prepare waterfrac treatment preparation according to claim 36; With

With effective volume and under the working pressure of waterfrac treatment, Xiang Jingzhong introduces described waterfrac treatment preparation,

Thus fractured well.

The method of 38. 1 kinds of fractured wells, described method comprises:

The waterfrac treatment preparation of preparation containing modification propping agent according to claim 1;

With effective volume and under the working pressure of waterfrac treatment, Xiang Jingzhong introduces described waterfrac treatment preparation;

Gel breaker preparation containing oxidation gel breaker or enzyme breaker is provided; With

The described gel breaker preparation of effective volume is added in the well of effective volume,

Thus fractured well.

39. according to method according to claim 38, and wherein, Xiang Jingzhong adds described gel breaker preparation and occurs in after Xiang Jingzhong introduces waterfrac treatment preparation.

40. according to method according to claim 39, and wherein, Xiang Jingzhong adds described gel breaker preparation to carry out before Xiang Jingzhong introduces waterfrac treatment preparation.

41. methods according to claim 40, wherein, the method is also included in the gel breaker preparation adding additional quantity after Xiang Jingzhong introduces waterfrac treatment preparation in well.

In the process of 42. geo-logical terrains penetrated by well in pressure break, wherein, the fracturing fluid containing propping agent is filled with in geo-logical terrain with pulsating pressure,

For reducing the method for the amount of the thickening material joined in fracturing fluid, comprise the modification propping agent of selection described in claim 1 as propping agent.

43. methods according to claim 42, wherein, described modification propping agent substantially completes hydration in first time in fracturing fluid was in conjunction with two hours.

44. methods according to claim 43, wherein, described modification propping agent substantially completes hydration in first time in fracturing fluid was in conjunction with 10 minutes.

45. 1 kinds of methods manufacturing modification propping agent, the method comprises:

Provide support the coating composition of agent blapharoplast and polymerizable fluid; With

Described propping agent blapharoplast applies the coating composition of described polymerizable fluid;

Wherein, the coating composition of described polymerizable fluid contains aquogel polymer, and, wherein, described aquogel polymer is localized with production modification propping agent on the surface of described propping agent blapharoplast.

46. methods according to claim 45, wherein, the method also comprises the step of dry described modification propping agent.

47. methods according to claim 45, wherein, the coating of the dry described polymerizable fluid of step of described drying to form the film of basic continous on the surface of described modification propping agent.

48. methods according to claim 45, wherein, described in be manufactured on the some place that uses described modification propping agent or its near occur.

49. methods according to claim 45, wherein, described propping agent blapharoplast comprises sand, pottery, low-density propping agent, the matrix of resin-coating and/or bauxite.

50. methods according to claim 45, wherein, described propping agent blapharoplast obtains near the some place of the described modification propping agent of use or its.

51. methods according to claim 45, wherein, described method be also included in propping agent blapharoplast and fluid polymer coating composition mixing step during or add the alcohol be selected from by the following group formed before: ethylene glycol, propylene glycol, glycerine, propyl alcohol and ethanol.

52. methods according to claim 45, wherein, described method be also included in propping agent blapharoplast and fluid polymer coating composition mixing step during or add afterwards reversion promotor.

53. methods according to claim 45, wherein, described method also comprises and add anti-hard caking agent in described modification propping agent.

54. methods according to claim 53, wherein, described anti-hard caking agent is selected from by the following group formed: hydrophobic layer material, fine dispersion particle material and linking agent.

55. 1 kinds of methods of propping agent manufacturing hydrogel coating, the method comprises:

Provide support agent blapharoplast and the preparation containing coating precursor, wherein, described coating precursor can form hydrogel coating by in-situ polymerization on the surface of described propping agent blapharoplast;

Preparation is applied to described propping agent blapharoplast; With

The described coating precursor contiguous with described propping agent blapharoplast is polymerized the propping agent applied to form hydrogel.

56. methods according to claim 55, wherein, the propping agent of described hydrogel coating contains the coated membrane of the basic continous on the surface of described propping agent blapharoplast.