CN103806890A - Method for obtaining consumption quantity of fracturing fluid and consumption quantity of acid liquor in fracture-vug type reservoir acid fracturing method - Google Patents

Abstract

The invention relates to a method for obtaining the consumption quantity of fracturing fluid and the consumption quantity of acid liquor in a fracture-vug type reservoir acid fracturing method. The method comprises the steps that after it is determined that a beneficial reservoir body exists in the fracture extension direction according to the ground stress and seismic data, the working procedures are carried out, wherein according to the working procedures, the needed length of an improvement half-fracture is determined according to the distance between the reservoir body and a shaft, the consumption quantity of the fracturing fluid needed for meeting the requirement of the length of the fracture under the condition of the appropriate discharging quantity is obtained through calculation on the premise that the needed facture length is determined, the discharging quantity of the acid liquor is optimized according to the time needed by loss of activity of the acid liquor, and the consumption quantity of the acid liquor is determined according to the discharging quantity of the acid liquor and the optimal contact time of acid rock when acid etching fractures of different blocks obtain highest flow conductivity. According to the method for obtaining the consumption quantity of the fracturing fluid and the consumption quantity of the acid liquor in the fracture-vug type reservoir acid fracturing method, the reliable basis is provided for the design, the effective rate and the construction production rate of acid fracturing construction are improved, and unwanted liquid waste is reduced as much as possible.

Description

The method of fracturing fluid consumption and acid solution consumption in the type reservoir acid fracturing method of acquisition seam hole

Technical field

The present invention relates to oil-gas field development technical field, be specifically related to a kind of method that obtains fracturing fluid consumption and acid solution consumption in seam hole type reservoir acid fracturing method.

Background technology

Tarim Basin is mainly seam hole type carbonate oil-gas reservoir, and acid fracturing is the Main Yield-increasing measure of this type of reservoir exploitation, and the at present annual acid fracturing wells of system in Tahe Oilfield reaches 300 mouthfuls of left and right.

Conventional carbonate reservoir acid fracturing design method is continued to use the design concept of sandstone fracturing, take production capacity or maximization of economic benefit as target, by software simulation, determines optimum liquid scale and discharge capacity etc. that is:, obtains thus the parameters such as the seam of simulation is long.The main Reservoir Body of system in Tahe Oilfield seam hole type carbonate reservoir is corrosion hole, (fracturing fluid is mainly used in making seam to the compound acid fracturing that main reforming technology is fracturing fluid+acid solution, acid solution kluftkarren wall produces certain flow conductivity), acid fracturing take link up pit shaft around favourable Reservoir Body as target, must first determine that in conjunction with seismic data the long energy of much seams ditch lead to Reservoir Body, further fracturing fluid scale and construction parameter etc. are determined in simulation more thus.Therefore, the inapplicable system in Tahe Oilfield seam of this method for designing hole type carbonate reservoir, must explore a kind of new acid fracturing design method that is suitable for stitching hole type Carbonate Reservoir.

Summary of the invention

Effective time when the dissimilar acid solution that the present invention records according to laboratory loses activity under different temperatures, bonding crack is wide, it is high to stitch and dummy joint long parameter and different displacements data obtain the EFFECTIVE RANGE of dissimilar acid solution under different temperatures and discharge capacity, optimizes acid solution discharge capacity; Sour rock optimum contacting time when the oil field different blocks acid-etched fracture recording according to laboratory obtains maximum flow conductivity and the acid solution discharge capacity of optimizing are determined best acid solution consumption.

The technical problem that the present invention solves is, a kind of method that obtains fracturing fluid consumption and acid solution consumption in seam hole type reservoir acid fracturing method is provided, for acid fracturing design provides reliable basis, improve acid fracturing construction efficient and build productive rate in, reduce as far as possible unnecessary liquid waste.

For solving the problems of the technologies described above, first the present invention determines that according to the distance between Reservoir Body and pit shaft required transformation dummy joint is long; Under the long definite prerequisite of required seam, then simulation obtains being applicable to discharge capacity and is issued to the long required fracturing fluid consumption of this seam; According to the acid solution required time-optimized acid solution discharge capacity that loses activity, the sour rock optimum contacting time while obtaining maximum flow conductivity in conjunction with different blocks acid-etched fracture is determined acid solution consumption; Utilize high temperature deep well Carbonate Reservoir down-hole microseism monitoring acid fracturing construction crack form, and for revising well designed method.

Specifically, the concrete technical scheme that the present invention adopts is, a kind of method that obtains fracturing fluid consumption and acid solution consumption in seam hole type reservoir acid fracturing method, and the method comprises following operation:

1) distance between Reservoir Body and pit shaft is defined as to minimum transformation dummy joint long;

2) calculate the well head pressure under different fracturing fluid discharge capacities by formula 1,

P _{well head}=P _extend+ P _{frictional resistance}-P _{fluid column}(1)

Wherein, P _{well head}for the well head pressure of calculating, unit is MPa,

P _extendfor stitching high extending pressure, P _extend=stratum extending pressure gradient × depth of reservoirs, unit is MPa,

P _{fluid column}for fluid column gravity in oil pipe, P _{fluid column}=fluid density × acceleration of gravity × liquid-column height, unit is MPa,

P _{frictional resistance}for pipe friction pressure, P _{frictional resistance}=pipe friction factor × pipe range, unit is MPa;

By the well head pressure under the different fracturing fluid discharge capacities that calculate, the fracturing fluid displacement data group of the well head pressure of selecting calculating within the scope of well head pressure-bearing;

3) from operation 2) fracturing fluid displacement data group, to meet and be greater than operation 1 according to dummy joint length corresponding to fracturing fluid discharge capacity) the long condition of the minimum transformation of gained dummy joint, selecting maximum fracturing fluid discharge capacity is best fracturing fluid discharge capacity, and dummy joint corresponding to this best fracturing fluid discharge capacity be long, stitch wide and seam is high for long, the best seam of best dummy joint is wide and best seam is high;

4) by operation 3) high, the best seam of long, the best seam of best dummy joint that obtains is wide, calculates acid solution discharge capacity according to formula 2,

Q=L _{dummy joint}× S _crack/ T _{acid solution}(2)

Wherein, Q is acid solution discharge capacity, and unit is m ³/ min,

L _{dummy joint}for operation 3) determine best dummy joint long, unit is m,

S _crackfor the total cross-sectional area in double-vane crack, S _crackhigh × best seam of=2 × best seam is wide, and unit is m ²,

T _{acid solution}for acid solution loses activity the required time under the reservoir temperature of wellblock, unit is min;

5) calculate acid solution consumption by formula 3,

M _{acid solution}=Q × T _contact(3)

Wherein, M _{acid solution}for acid solution consumption, unit is m ³,

Q is acid solution discharge capacity, and unit is m ³/ min,

T _contactfor sour rock optimum contacting time in real well, unit is min.

The method of fracturing fluid consumption and acid solution consumption in the type reservoir acid fracturing method of aforesaid acquisition seam hole, wherein, operation 5) in, described acid solution is gel acid, cross-linked acid or the acid that becomes sticky.

The method of fracturing fluid consumption and acid solution consumption in the type reservoir acid fracturing method of aforesaid acquisition seam hole, wherein, operation 4) described in acid solution required time that loses activity under the reservoir temperature of wellblock be that hydrochloric acid loses activity the required time under the reservoir temperature of wellblock, its assay method is: according to the chemical reaction equation of hydrochloric acid and calcium carbonate, by measuring under the reservoir temperature of wellblock, acid solution is reacted the Δ m of poor quality of front and back rock beam with rock beam in groove by guiding gutter, the hydrochloric acid mole that calculates consumption is 2 Δ m/100, calculates the rear acid solution molar concentration of reaction by formula 4:

C=(C _initially× Q ' × t-2 Δ m/100)/(Q ' × t) (4)

Wherein, C is acid solution molar concentration after the reaction t time, and unit is mol/L;

C _initiallyfor reacting front acid solution molar concentration, unit is mol/L;

The acid solution discharge capacity of Q ' when testing, unit is L/min;

T is the reaction time of acid solution and rock beam, and unit is min;

Δ m is the of poor quality of rock beam before and after acid solution is reacted with rock beam in groove by guiding gutter, and unit is g;

By formula 4 acquired results, calculate acid solution according to formula 5 and lose activity the required time under the reservoir temperature of wellblock:

T/T _{acid solution}=(C _initially-C)/(C _initially-C _{lost efficacy}) (5)

Wherein, T _{acid solution}for acid solution loses activity the required time under the reservoir temperature of wellblock, unit is min;

C is acid solution molar concentration after the reaction t time, and unit is mol/L;

C _initiallyfor reacting front acid solution molar concentration, unit is mol/L;

C _{lost efficacy}acid solution molar concentration during for inefficacy, unit is mol/L;

T is the reaction time of acid solution and rock beam, and unit is min.

The method of fracturing fluid consumption and acid solution consumption in the type reservoir acid fracturing method of aforesaid acquisition seam hole, wherein, operation 5) described in real well the preparation method of sour rock optimum contacting time be:

1) obtain the flow conductivity data group of sour rock in the time that be 10min, 30min, 45min, 60min time of contact under the effective clossing pressure in wellblock, its preparation method is: rock beam is contacted after 10min, 30min, 45min, 60min to the flow conductivity of test rock beam with acid solution;

2) calculated effective clossing pressure of real well by formula 6,

P _closed=G _closed× H _reservoir-H _reservoir/ 100 × F _stratum(6)

Wherein, P _closedfor effective clossing pressure of real well, unit is MPa,

G _closedfor clossing pressure gradient, unit is MPa/m,

H _reservoirfor depth of reservoirs, unit is m,

F _stratumfor reservoir pressure coefficient;

3) effective clossing pressure of the real well calculating according to formula 6, from flow conductivity data group, selecting effective clossing pressure of the effective clossing pressure in wellblock and real well time of contact identical or when approaching acid-etched fracture under condition most and obtaining maximum flow conductivity is sour rock optimum contacting time.

In the type reservoir acid fracturing method of aforesaid acquisition seam hole, the method for fracturing fluid consumption and acid solution consumption, wherein, while carrying out acid fracturing construction, adopts 31/2 " oil pipe and 27/8 " oil pipe.

The present invention is directed to the particularity of system in Tahe Oilfield seam hole type Carbonate Reservoir, a kind of design concept and method that obtains acid solution consumption in the type Carbonate Reservoir acid fracturing method of seam hole proposed, and adopt high temperature deep well Carbonate Reservoir down-hole microseism monitoring acid fracturing construction crack form, for revising well designed method.The method, for the acid fracturing design of seam hole type Carbonate Reservoir provides foundation, not only can improve acid fracturing and constructs efficient and build productive rate, can also reduce unnecessary liquid waste.

The present invention determines that according to the distance between Reservoir Body and pit shaft required transformation seam is long, and under the long definite prerequisite of required seam, simulation obtains being applicable to required fracturing fluid scale under discharge capacity; According to the acid solution required time-optimized acid filling discharge capacity that loses activity, the sour rock optimum contacting time while obtaining maximum flow conductivity in conjunction with different blocks acid-etched fracture is determined acid solution consumption, is a kind of new foundation of preferably providing of acid solution consumption again.

Accompanying drawing explanation

Fig. 1 is near favourable Reservoir Body distribution map S72-17 well wellblock.

Fig. 2 is acid fracturing fracture pattern and the orientation that S72-17 well monitors.

The specific embodiment

Conventional seam hole type Carbonate Reservoir acid fracturing method is that Optimizing Reconstruction seam is long using production capacity or maximization of economic benefit as target, and determines Optimum Fracturing liquid consumption under prerequisite transformation seam is long, has caused unnecessary liquid waste.

First the present invention determines that according to the distance between Reservoir Body and pit shaft required transformation dummy joint is long; Under the long definite prerequisite of required seam, simulation obtains being applicable to required fracturing fluid consumption under discharge capacity; According to the acid solution required time-optimized acid solution discharge capacity that loses activity, the sour rock optimum contacting time while obtaining maximum flow conductivity in conjunction with different blocks acid-etched fracture is determined acid solution consumption; Utilize high temperature deep well Carbonate Reservoir down-hole microseism monitoring acid fracturing construction crack form, and for revising well designed method.The method not only can improve acid fracturing constructs efficient and builds productive rate, can also reduce unnecessary liquid waste.

Describe the method that the present invention obtains fracturing fluid consumption and acid solution consumption in seam hole type reservoir acid fracturing method below in detail, to set forth the feature of the method applied in the present invention and to prove effect of the present invention.

According to the method for fracturing fluid consumption and acid solution consumption in the type reservoir acid fracturing method of acquisition of the present invention seam hole, exist after favourable Reservoir Body, comprise following operation utilizing geostatic stress and seismic data to determine in fracture extension direction:

1) distance between Reservoir Body and pit shaft is defined as to minimum transformation dummy joint long.

2) by P _{well head}=P _extend+ P _{frictional resistance}-P _{fluid column}calculate the well head pressure under different fracturing fluid discharge capacities, wherein, P _{well head}for calculative well head pressure, unit is MPa.P _extendfor stitching high extending pressure, P under different fracturing fluid discharge capacities _extend=stratum extending pressure gradient × depth of reservoirs, unit is MPa.Stratum extending pressure gradient and depth of reservoirs are the intrinsic parameter in stratum, can measure by existing routine techniques.

P _{fluid column}for fluid column gravity in oil pipe, P _{fluid column}=fluid density × acceleration of gravity × liquid-column height, unit is MPa.

P _{frictional resistance}for pipe friction pressure, P _{frictional resistance}=pipe friction factor × pipe range, unit is MPa.

Here " different fracturing fluid discharge capacity " refers to according to experience, selects suitable one group of fracturing fluid discharge capacity, for example 4.5m ³/ min, 5.0m ³/ min, 5.5m ³/ min, 6.0m ³/ min etc., then bring into respectively in above-mentioned formula and calculate, and draw respectively well head pressure.By the well head pressure under the different fracturing fluid discharge capacities that calculate, the fracturing fluid discharge capacity composition fracturing fluid displacement data group of the well head pressure of selecting calculating within the scope of well head pressure-bearing.Pipe friction factor can be obtained by conventional method, as adopted Ч e р н и к и н, method (Ч e р н и к и н, the A.B. of A.B..The calculating of the pipeline hydraulic coefficient of friction resistance, Oil & Gas Storage, 1999,18(2) 26-28) in method calculate, also can calculate according to the method in " calculating falls in HG/T20570.7-95 pipeline pressure ".

In operation 3) front, need to consider whether to need control seam high according to wellblock water body development situation, be specially: 1) if wellblock water body agensis, do not consider that control seam is high, within the scope of well head pressure-bearing, improve fracturing fluid discharge capacity as far as possible, because fracturing fluid discharge capacity is larger, the seam obtaining under identical fracturing fluid consumption is longer, and fracturing fluid consumption required in the time reaching set seam length is less; 2) if wellblock water body development, under the prerequisite of clear and definite oil-water interfaces, the fracture height under simulation different displacements is extended situation, guarantee to stitch high extension not ditch lead to bottom water body, grow up under the long prerequisite of minimum transformation dummy joint meeting dummy joint, select high fracturing fluid discharge capacity construction as far as possible.

3) from operation 2) fracturing fluid displacement data group, to meet and be greater than operation 1 according to dummy joint length corresponding to fracturing fluid discharge capacity) the long condition of the minimum transformation of gained dummy joint, selecting maximum fracturing fluid discharge capacity is best fracturing fluid discharge capacity, and dummy joint corresponding to this best fracturing fluid discharge capacity be long, stitch wide and seam is high for long, the best seam of best dummy joint is wide and best seam is high.

Dummy joint in fracturing fluid displacement data group under each fracturing fluid discharge capacity is long, it is wide to stitch, stitch and highly can calculate by conventional method, for example, adopt " fracturing design value computational methods " (Wang Hongxun, Zhang Shicheng.Petroleum industry publishing house) method of 178-188 page, calculate method and the following formula of crevice volume rates of change according to " fracturing design value computational methods " 184 pages, calculate dummy joint long, stitch wide, stitch high:

$\begin{array}{c}{W}_0\left(x\right)=\\ \frac{2\sqrt{2}(1-v^2)}{\sqrt{\mathrm{\π}}E}{K}_C\sqrt{H\left(x\right)}+\frac{4(1-v^2)}{\mathrm{\πE}}(S_2-S_1)H_p[\ln H\left(x\right)+\sqrt{H^2\left(x\right)-H_p^2}-\ln H_p]\\ \frac{\mathrm{dH}\left(x\right)}{\mathrm{dx}}=\frac{64}{\mathrm{\π}}\frac{q\left(x\right)\mathrm{\μ}\left(x\right)}{e\left(x\right)W_0^3\left(x\right)}\end{array}$

Also can adopt in addition conventional software simulation obtain in fracturing fluid displacement data group the dummy joint under each fracturing fluid discharge capacity long, stitch wide, stitch highly, for example, in a specific embodiment, adopt and in FracproPT software, intend three-dimensional FRACTURING DESIGN computational methods and obtain.The parameter wherein relating to, such as fracturing fluid friction, fracturing fluid rheology, fracturing fluid leak etc., formation temperature, degree of porosity, permeability etc., and the parameter such as reservoir stress, young's modulus of elasticity, poisson's ratio, fracture toughness all adopts prior art conventional method to obtain.

4) by operation 3) high, the best seam of long, the best seam of best dummy joint that obtains is wide, according to Q=L _{dummy joint}× S _crack/ T _{acid solution}calculate acid solution discharge capacity, wherein, Q is acid solution discharge capacity, and unit is m ³/ min, L _{dummy joint}for operation 4) determine best dummy joint long, unit is m, S _crackfor the total cross-sectional area in double-vane crack, S _crackhigh × best seam of=2 × best seam is wide, and unit is m ², T _{acid solution}for acid solution loses activity the required time under the reservoir temperature of wellblock, unit is min;

Wherein, acid solution required time that loses activity under the reservoir temperature of wellblock is hydrochloric acid and loses activity the required time under the reservoir temperature of wellblock, its assay method is: according to the chemical reaction equation of hydrochloric acid and calcium carbonate, by measuring under the reservoir temperature of wellblock, acid solution is reacted the Δ m of poor quality of front and back rock beam with rock beam in groove by guiding gutter, the hydrochloric acid mole that calculates consumption is 2 Δ m/100, by C=(C _initially× Q ' × t-2 Δ m/100)/(Q ' × t) calculate the rear acid solution molar concentration of reaction, in conjunction with t/T _{acid solution}=(C _{just begin}-C)/(C _initially-C _{lost efficacy}) calculate acid fluid system and lose activity the required time under the reservoir temperature of wellblock, wherein, C for the reaction t time after acid solution molar concentration, unit is mol/L, C _initiallyfor reacting front acid solution molar concentration, unit is mol/L, and the acid solution discharge capacity of Q ' when testing, can be arbitrary value, does not affect T _{acid solution}calculating, generally rule of thumb choose suitable acid solution discharge capacity, unit is L/min, t is the sour rock reaction time, can be the arbitrary value that sour rock reacted completely in the time, unit is min, T _{acid solution}for acid solution loses activity the required time under the reservoir temperature of wellblock, unit is min, C _{lost efficacy}molar concentration while inefficacy for acid solution, unit is mol/L.

5) by P _closed=G _closed× H _reservoir-H _reservoir/ 100 × F _stratumcalculate effective clossing pressure of real well, flow conductivity data group in conjunction with sour rock under the effective clossing pressure in wellblock in the time that be 10min, 30min, 45min, 60min time of contact, from data group, select the identical or sour rock optimum contacting time when approaching acid-etched fracture under condition and obtaining maximum flow conductivity of effective clossing pressure of the effective clossing pressure in wellblock and real well, by M _{acid solution}=Q × T _contactcalculate acid solution consumption; Wherein, P _closedfor effective clossing pressure of real well, unit is MPa, G _closedfor clossing pressure gradient, unit is MPa/m, H _reservoirfor depth of reservoirs, unit is m, F _stratumfor reservoir pressure coefficient; M _{acid solution}for acid solution consumption, unit is m ³, Q is operation 4) and the acid solution discharge capacity that calculates, unit is m ³/ min, T _contactsour rock optimum contacting time when acid-etched fracture obtains maximum flow conductivity in real well, unit is min.

Wellblock difference, effective clossing pressure of wellblock is also different.Be not limited to 10min, 30min, 45min, 60min the time of contact of acid rock, and those skilled in the art also can rule of thumb choose other different times of contact.

Operation 5) in the preparation method of the flow conductivity data group of acid rock in wellblock in the time that be 10min, 30min, 45min, 60min time of contact be: rock beam is contacted after 10min, 30min, 45min, 60min with acid solution, utilizes acid-etched fracture guide instrument to test the flow conductivity of rock beam under the clossing pressure of wellblock.

In the type reservoir acid fracturing method of aforesaid acquisition seam hole, the method for fracturing fluid consumption and acid solution consumption, while carrying out acid fracturing construction, adopts 31/2 " oil pipe and 27/8 " oil pipe.

The method of acid solution consumption in the type Carbonate Reservoir acid fracturing method of aforesaid acquisition seam hole, gained dummy joint is long, seam high when utilizing down-hole microseism monitoring construction fracture pattern carry out error comparative analysis, binding analysis result is further revised well designed method.

The present invention adopt of the fracturing fluid source and consist of:

Frozen glue: adopt the fracturing fluid goods of telling that to breathe out model that down-hole technical operation company sells be TH-HPG, it consists of: 0.5%HPG melon glue+1.0%LZ-1 cleanup additive+1.0%LP-1 demulsifier+0.1%LK-7 bactericide+0.02%pH value conditioning agent+0.5%LK-6 temperature stability agent+1.0%LK-8 clay stabilizer, and all the other are water; Wherein, melon glue is generally HPG.

As long as the acid solution with strong acid erosion ability all can be used for the present invention, the preferred gel acid of the present invention, cross-linked acid and the acid that becomes sticky; Described gel acid, cross-linked acid and the sour composition that becomes sticky are respectively:

Gel acid: the gel acid goods that the model that adopts Xi'an super new science and technology Development Co., Ltd to sell is CX-208, it consists of: 20%HCl+1.0%CX-208 gelling agent+2.0%YHS-2 high-temperature corrosion inhibitor+1.0%CX-307 breakdown of emulsion cleanup additive+0.15%CX-301 ferrous stability, all the other are water.

Cross-linked acid: the frozen glue acid goods that the model that adopts Beijing liberal-mindedness and vigorous endurance bounties energy technology Co., Ltd to sell is ECA-160, it consists of: thickening agent for 20%HCl+0.9% acid fracturing-ECA-1+2.0% is corrosion inhibiter-EEH+1.0% cleanup additive-EEZ+1.0% demulsifier-EEP+1.0% ferrous stability-EET+3.5% crosslinking agent-ECA+0.03% gel breaker-ECB for acid fracturing for acid fracturing for acid fracturing for acid fracturing for acid fracturing for acid fracturing, and all the other are water.

Acid becomes sticky: the sour goods that become sticky that the model that adopts Sichuan beidellite oil tech Development Co., Ltd to sell is BD1-11, it consists of: 20%HCl+0.8%BD1-11 sour gelling agent+2.0%BD120C high-temperature corrosion inhibitor+1.0%BD1-2 ferrous stability+1.0%BD1-3 demulsifier+1.0%BD1-5 cleanup additive that becomes sticky, all the other are water.

In addition, it should be noted that, conventional those reagent as pH value conditioning agent, melon glue, demulsifier, bactericide, cleanup additive, breakdown of emulsion cleanup additive, temperature stability agent, clay stabilizer, crosslinking agent, gelling agent, corrosion inhibiter and ferrous stability in every this area all can be used in the application.For example, gelling agent can be butyl acrylate, and corrosion inhibiter can be KI, ferrous stability can be ascorbic acid, cleanup additive can be APES, and demulsifier can be SYNPERONIC PE/F68, and activator can be buserelin.Cleanup additive described in the application and breakdown of emulsion cleanup additive adopt APES composed as follows conventionally: NPE (NPEO) accounts for 80%～85%, OPEO (OPEO) accounts for more than 15%, and binonylphenol and dodecyl phenol polyethenoxy ether respectively account for 1%.

Lose activity under the reservoir temperature of the wellblock hydrochloric acid that is determined as of required time of aforementioned acid solution loses activity the required time under the reservoir temperature of wellblock, its assay method is: it has been generally acknowledged that acid strength reach initial concentration 10% time, acid solution loses activity, it is 6.2mol/L that the application's acid solution used contains mass fraction 20%() hydrochloric acid, be 1mol/L when concentration of hydrochloric acid is reduced to 2%() time acid solution lose activity.Utilize acid-etched fracture guide instrument unit simulation acid rock course of reaction, acid solution is selected from gel acid, cross-linked acid, acid becomes sticky, rock beam adopts Ordovician of Tahe oil to appear (carbonate content is greater than 95%), according to the chemical reaction equation of hydrochloric acid and calcium carbonate, by measuring under the reservoir temperature of wellblock, acid solution is reacted the Δ m of poor quality of front and back rock beam with rock beam in groove by guiding gutter, the hydrochloric acid mole that calculates consumption is 2 Δ m/100, by C=(C _initially× Q ' × t-2 Δ m/100)/(Q ' × t) calculate the rear acid solution molar concentration of reaction, in conjunction with t/T _{acid solution}=(C _initially-C)/(C _initially-C _{lost efficacy}) calculate acid fluid system and lose activity the required time under the reservoir temperature of wellblock, wherein, C for the reaction t time after acid solution molar concentration, unit is mol/L, C _{just begin}for reacting front acid solution molar concentration, unit is mol/L, and the acid solution discharge capacity of Q ' when testing, can be arbitrary value, does not affect T _{acid solution}calculating, generally rule of thumb choose suitable acid solution discharge capacity, unit is L/min, t is the reaction time of acid solution and rock beam, unit is min, T _{acid solution}for acid solution loses activity the required time under the reservoir temperature of wellblock, unit is min, C _{lost efficacy}molar concentration while inefficacy for acid solution, unit is mol/L.

The preparation method of the flow conductivity data group of aforementioned wellblock acid rock in the time that be 10min, 30min, 45min, 60min time of contact is: testing acid solution used is the conventional gel acid of system in Tahe Oilfield, cross-linked acid, the acid that becomes sticky, and rock beam adopts Ordovician of Tahe oil to appear (carbonate content is greater than 95%); Rock beam is contacted with acid solution after certain hour (as 10min, 30min, 45min, 60min), utilize acid-etched fracture guide instrument test rock beam flow conductivity of (as 10MPa, 20MPa, 30MPa, 40MPa) under the clossing pressure of wellblock.

While carrying out acid fracturing construction, adopt 31/2 " oil pipe and 27/8 " oil pipe, for example, can adopt 31/2 " EUE external upset tubing/31/2 " TP-JC oil pipe and 27/8 " EUE external upset tubing/27/8 " TP-JC oil pipe.

Below, enumerate embodiment the present invention is further described, but the present invention is not limited to following embodiment.

Embodiment

The device, the raw material that in the assay method of sour rock optimum contacting time when acid solution in embodiment is below lost activity under the reservoir temperature of wellblock under the effective clossing pressure of assay method and wellblock of required time to acid-etched fracture obtains maximum flow conductivity, use are described as follows:

Acid-etched fracture guide instrument device: Hai'an oil scientific research Instrument Ltd., model is SNF-1.

Rock beam: adopt Ordovician of Tahe oil to appear, wherein carbonate content is greater than 95%.

Below by the field trial of system in Tahe Oilfield being described in detail to acid fracturing method of the present invention.

Embodiment 1(maintains secrecy and tests)

To system in Tahe Oilfield S72-17 well acid fracturing construction simulation

The conventional acid solution of system in Tahe Oilfield is gel acid, the general cross-linked acid that adopts in the time that sand pressure break is taken in needs acid, and local metafiltration mistake is general when larger adopts the acid that becomes sticky to fall filter.This well intrinsic fracture is grown, and leak-off is larger, the acid construction of selecting to become sticky, and by mass%, it is composed as follows:

Acid becomes sticky: the sour goods that become sticky that the model that adopts Sichuan beidellite oil tech Development Co., Ltd to sell is BD1-11, it consists of: 20%HCl+0.8%BD1-11 sour gelling agent+2.0%BD120C high-temperature corrosion inhibitor+1.0%BD1-2 ferrous stability+1.0%BD1-3 demulsifier+1.0%BD1-5 cleanup additive that becomes sticky, all the other are water.

In addition, it should be noted that, conventional those reagent as gelling agent, demulsifier, cleanup additive, high-temperature corrosion inhibitor and ferrous stability in every this area all can be used in the application.For example, gelling agent can be butyl acrylate, and corrosion inhibiter can be KI, and ferrous stability can be ascorbic acid, and cleanup additive can be APES, and demulsifier can be SYNPERONIC PE/F68.Cleanup additive described in the application adopts APES composed as follows conventionally: NPE (NPEO) accounts for 80%～85%, OPEO (OPEO) accounts for more than 15%, and binonylphenol and dodecyl phenol polyethenoxy ether respectively account for 1%.

As shown in Figure 1, S72-17 well wellblock maximum horizontal stress direction is probably 15 ° of E15S(east by south), minimum level stress direction is probably 15 ° of N15E(norths by east), according to crack, perpendicular to minimum principal stress crack initiation, this well fracture initiation direction should be E15S.From the construct plane amplitude change rate figure of target interval of Fig. 1, in E15S direction, have favourable Reservoir Body, and this side up Reservoir Body is apart from approximately 77m of this well shaft distance.Fig. 2 is acid fracturing fracture pattern and the orientation that S72-17 monitors, and its fracture extension direction is consistent with Fig. 1 fracture extension direction.

So according to above-mentioned analysis, minimum transformation dummy joint length should be 77m.

This well depth of reservoirs is 5513m, and reservoir temperature is 125 ℃, and reservoir intrinsic fracture is grown (leak-off is large), stratum extending pressure gradient 0.0162MPa/m, clossing pressure gradient 0.0145MPa/m, reservoir pressure coefficient 1.1, at the bottom of this wellblock growth, water is grown, and oil-water interfaces are probably positioned at 5548m.Oil pipe: 31/2 " 5400m+27/8 " 10m.According to P _{well head}=P _extend+ P _friction-P _{fluid column}, can calculate under different fracturing fluid discharge capacities well head pressure as shown in table 1 below, wherein, P _extendfor stitching high extending pressure, P under different fracturing fluid discharge capacities _extend=stratum extending pressure gradient × depth of reservoirs, unit is MPa, P _{fluid column}for fluid column gravity in oil pipe, P _{fluid column}=fluid density × acceleration of gravity × liquid-column height, unit is MPa, P _frictionfor pipeline friction pressure, P _friction=pipeline friction factor × pipe range, unit is MPa.

Well head pressure under the different fracturing fluid discharge capacities of table 1

Note: system in Tahe Oilfield acid fracturing S72-17 well well head is 105 type well heads, pressure-bearing 105Mpa.

Calculating well head pressure under the different displacements of fracturing fluid shown in table 1 is within the scope of well head pressure-bearing.

Utilize " fracturing design value computational methods " (Wang Hongxun, Zhang Shicheng.Petroleum industry publishing house) to calculate fracturing fluid discharge capacity be 5m for the computational methods of 178-188 page ³/ min and 6m ³/ min and fracturing fluid consumption are respectively 180m ³, 200m ³, 220m ³, 250m ³dummy joint under condition is long, it is wide to stitch, it is high to stitch, and result is as shown in table 2 and table 3.

Table 2 fracturing fluid discharge capacity is 5m ³/ min and fracturing fluid consumption are respectively 180m ³, 200m ³, 220m ³, 250m ³dummy joint under condition is long, it is wide to stitch, it is high to stitch

Table 3 fracturing fluid discharge capacity is 6m ³/ min and fracturing fluid consumption are respectively 200m ³, 220m ³, 250m ³dummy joint under condition is long, it is wide to stitch, it is high to stitch

At the bottom of this wellblock growth, water is grown, and needs to consider that control seam is high in construction.This well construction well section middle part degree of depth 5513m, apart from bottom oil-water interfaces 35m, fracturing fluid discharge capacity is 5m ³when/min, dummy joint is grown up long in minimum transformation dummy joint, and when dummy joint length is for 83.2m, the high 31.8m of lower seam, links up less than water body, brings up to 6m and work as fracturing fluid discharge capacity ³when/min, dummy joint is grown up long in minimum transformation dummy joint, when dummy joint length is for 85.4m, and the high 35.9m of lower seam, ditch leads to bottom water body.Therefore preferred fracturing fluid discharge capacity 5m ³/ min, and selection fracturing fluid consumption is 220m ³, now dummy joint reaches 83.2m, meets dummy joint and grows up in the requirement of the long 77m of minimum transformation dummy joint.

It has been generally acknowledged that acid strength reach initial concentration 10% time, acid solution loses activity.It is 6.2mol/L that the application's acid solution used contains mass fraction 20%() hydrochloric acid, be 1mol/L when concentration of hydrochloric acid is reduced to 2%() time acid solution lose activity.The dissimilar acid solution determined by laboratory (preferably gel acid, cross-linked acid, acid becomes sticky) loses activity the required time under different temperatures, as shown in table 4.

The effective acting time of different acid solutions under different temperatures is determined in table 4 laboratory

This well intrinsic fracture is grown, and leak-off is larger, the acid construction of selecting to become sticky.In addition, wellblock reservoir temperature is 125 ℃, so select the effective time 20.5min of acid in the time of 125 ℃ that become sticky.

Be 83.2m by above-mentioned definite dummy joint length, seam height is 61.5m, and stitching wide is 1.01cm, the total cross-sectional area S in double-vane crack _crack=2 × stitch high × stitch wide, i.e. S _crack=2 × 61.5 × 1.01/100=1.24m ².Suppose that acid solution discharge capacity is Q m ³/ min, Q/1.24 is the linear velocity of acid solution in crack, and it is the EFFECTIVE RANGE of acid solution under Q that linear velocity is multiplied by acid solution effective time again, has Q/1.24 × 20.5>=83.2, obtains Q>=5.03m ³/ min, determines acid solution discharge capacity 5.5m thus ³/ min can meet construction requirement completely.

Acid (acid becomes sticky) rock optimum contacting time when the definite different blocks acid-etched fracture in laboratory obtains maximum flow conductivity is as shown in table 5.

Flow conductivity under table 5 acid (acid becomes sticky) rock different times of contact

The effective clossing pressure of this well is: 0.0145 × 5513-55.13 × 1.1=19.3MPa.Under the known effective clossing pressure 20MPa of table 5 data, when sour rock contact 45min, flow conductivity reaches maximum.Acid (acid becomes sticky) rock optimum contacting time when acid solution discharge capacity is multiplied by acid-etched fracture and obtains maximum flow conductivity, obtains best acid solution consumption, i.e. 5.5m ³/ min × 45min=247m ³, consider that the injection of acid solution is progressively to put forward discharge capacity, when low discharge capacity, penetration range is lower, therefore, the acid solution 10m that has more than needed ³round to obtain 260m ³acid becomes sticky.

Simulate effect is evaluated

By analyzing above, determine this well fracturing fluid scale 220m ³, fracturing fluid operational discharge capacity 5m ³/ min; Sour consumption 260m becomes sticky ³, sour operational discharge capacity 5.5m becomes sticky ³/ min.

Fracture pattern when down-hole microseism detects the S72-17 well practice of construction obtaining is as shown in table 6.

Fracture pattern when table 6 practice of construction

Validity event	Seam group leader (m)	Seam group high (m)	Inclination angle (degree)
				78	181.25	53.88	E13S

Interpretation of result:

, there is favourable Reservoir Body in E13S direction in fracture extension direction E13S, substantially identical with this wellblock stress direction;

Seam group leader 181.25m, i.e. the long 90.625m of dummy joint, with design error is: (90.625-83.2)/83.2 × 100%=8.9%;

Stitch high 53.88m, with design error be: (61.5-53.88)/61.5 × 100%=12.4%.

Method and the on-the-spot actual goodness of fit that the present invention obtains acid solution consumption in the type Carbonate Reservoir acid fracturing method of seam hole are higher.

Claims (4)

1. a method that obtains fracturing fluid consumption and acid solution consumption in seam hole type reservoir acid fracturing method, comprises following operation:

1) distance between Reservoir Body and pit shaft is defined as to minimum transformation dummy joint long;

2) calculate the well head pressure under different fracturing fluid discharge capacities by formula 1,

P _{well head}=P _extend+ P _{frictional resistance}-P _{fluid column}(1)

Wherein, P _{well head}for the well head pressure of calculating, unit is MPa,

P _extendfor stitching high extending pressure, P _extend=stratum extending pressure gradient × depth of reservoirs, unit

For MPa,

P _{fluid column}for fluid column gravity in oil pipe, P _{fluid column}=fluid density × acceleration of gravity × liquid-column height,

Unit is MPa,

P _{frictional resistance}for pipe friction pressure, P _{frictional resistance}=pipe friction factor × pipe range, unit is MPa;

By the well head pressure under the different fracturing fluid discharge capacities that calculate, the fracturing fluid displacement data group of the well head pressure of selecting calculating within the scope of well head pressure-bearing;

3) from operation 2) fracturing fluid displacement data group, to meet and be greater than operation 1 according to dummy joint length corresponding to fracturing fluid discharge capacity) the long condition of the minimum transformation of gained dummy joint, selecting maximum fracturing fluid discharge capacity is best fracturing fluid discharge capacity, and dummy joint corresponding to this best fracturing fluid discharge capacity be long, stitch wide and seam is high for long, the best seam of best dummy joint is wide and best seam is high;

4) by operation 3) high, the best seam of long, the best seam of best dummy joint that obtains is wide, calculates acid solution discharge capacity according to formula 2,

Q=L _{dummy joint}× S _crack/ T _{acid solution}(2)

Wherein, Q is acid solution discharge capacity, and unit is m ³/ min,

L _{dummy joint}for operation 3) determine best dummy joint long, unit is m,

S _crackfor the total cross-sectional area in double-vane crack, S _crackhigh × best seam of=2 × best seam is wide, unit

For m ²,

T _{acid solution}for acid solution loses activity the required time under the reservoir temperature of wellblock, unit is min;

5) calculate acid solution consumption by formula 3,

M _{acid solution}=Q × T _contact(3)

Wherein, M _{acid solution}for acid solution consumption, unit is m ³,

Q is acid solution discharge capacity, and unit is m ³/ min,

T _contactfor sour rock optimum contacting time in real well, unit is min.

2. the method for fracturing fluid consumption and acid solution consumption in the type reservoir acid fracturing method of acquisition seam according to claim 1 hole, wherein, operation 5) in, described acid solution is gel acid, cross-linked acid or the acid that becomes sticky.

3. the method for fracturing fluid consumption and acid solution consumption in the type reservoir acid fracturing method of acquisition seam according to claim 1 and 2 hole, wherein, operation 4) described in acid solution required time that loses activity under the reservoir temperature of wellblock be that hydrochloric acid loses activity the required time under the reservoir temperature of wellblock, its assay method is: according to the chemical reaction equation of hydrochloric acid and calcium carbonate, the Δ m of poor quality of rock beam before and after reacting with rock beam in groove by guiding gutter by acid solution under the reservoir temperature of measurement wellblock, the hydrochloric acid mole that calculates consumption is 2 Δ m/100, calculate the rear acid solution molar concentration of reaction by formula 4:

C=(C _initially× Q ' × t-2 Δ m/100)/(Q ' × t) (4)

Wherein, C is acid solution molar concentration after the reaction t time, and unit is mol/L;

C _initiallyfor reacting front acid solution molar concentration, unit is mol/L;

The acid solution discharge capacity of Q ' when testing, unit is L/min;

T is the reaction time of acid solution and rock beam, and unit is min;

Δ m is the of poor quality of rock beam before and after acid solution is reacted with rock beam in groove by guiding gutter, unit

For g;

By formula 4 acquired results, calculate acid solution according to formula 5 and lose activity the required time under the reservoir temperature of wellblock:

T/T _{acid solution}=(C _initially-C)/(C _initially-C _{lost efficacy}) (5)

Wherein, T _{acid solution}for acid solution loses activity the required time under the reservoir temperature of wellblock, unit is min;

C is acid solution molar concentration after the reaction t time, and unit is mol/L;

C _initiallyfor reacting front acid solution molar concentration, unit is mol/L;

C _{lost efficacy}acid solution molar concentration during for inefficacy, unit is mol/L;

T is the reaction time of acid solution and rock beam, and unit is min.

4. according to the method for fracturing fluid consumption and acid solution consumption in the acquisition seam hole type reservoir acid fracturing method described in claim 1-3 any one, wherein, operation 5) described in real well the preparation method of sour rock optimum contacting time be:

1) obtain the flow conductivity data group of sour rock in the time that be 10min, 30min, 45min, 60min time of contact under the effective clossing pressure in wellblock, its preparation method is: rock beam is contacted after 10min, 30min, 45min, 60min to the flow conductivity of test rock beam with acid solution;

2) calculated effective clossing pressure of real well by formula 6,

P _closed=G _closed× H _reservoir-H _reservoir/ 100 × F _stratum(6)

Wherein, P _closedfor effective clossing pressure of real well, unit is MPa,

G _closedfor clossing pressure gradient, unit is MPa/m,

H _reservoirfor depth of reservoirs, unit is m,

F _stratumfor reservoir pressure coefficient;

3) effective clossing pressure of the real well calculating according to formula 6, from flow conductivity data group, selecting effective clossing pressure of the effective clossing pressure in wellblock and real well time of contact identical or when approaching acid-etched fracture under condition most and obtaining maximum flow conductivity is sour rock optimum contacting time.

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