US2898999A

US2898999A - Disposable rubber products

Info

Publication number: US2898999A
Application number: US550247A
Authority: US
Inventors: Paul G Carpenter
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1955-12-01
Filing date: 1955-12-01
Publication date: 1959-08-11
Anticipated expiration: 1976-08-11

Description

Aug. l1, 1959 P. G. CARPENTER DISPOSABLE RUBBER PRODUCTS Filed Deo IN VEN TOR. P G. :ARPENTER #miam M4 LA T TOR/v5 V5 United States Patent msPosABLE RUBBER PRODUCTS Paul G. Carpenter, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Application December 1, 1955, Serial No. 550,247 8 Claims. (Cl. `166-46) This invention relates to disposable rubbery products of manufacture. In one aspect, the invention relates -to the method of disposing of, in situ, disposable rubbery products.

In various instances it is necessary to use a temporary member in the set-up of a system or machine, and thereafter, to remove the temporary member when its usefulness or function has been served. For example, it is sometimes desired to utilize a temporary rubber spacer to hold the valve stem of a remote valve in the open or closed position, and subsequently, to remove the spacer when the position of the valve is to be altered, i. e., closed from an open position or vice versa. Another example is when 'the corners of heavy machinery are mounted on temporary rubber spacers, and the removal of the spacers is deemed necessary to set the machinery in its proper foundation. The foregoing examples illustrate situations wherein the temporary rubbery spacer undergoes compressive stress inasmuch as a weight or force is continually maintained on the spacer. A further example is the use of rubber packers in oil wells. The packer is positioned in the lower portion .of the well in the annular space between the casing and the tubing thus sealing the annulus. However, when pressures in the oil reservoir have fallen to the point where a well will not produce by natural energy, some method of artificial lift must be used. For this purpose an oil-well pump, such as a reciprocating pump, is lowered through the tubing to the desired depth; the oil-Well pump being connected to a pumping unit at the surface by means of sucker rods. In actual operation, the oil-well pump literally lifts the uid from the oil formation up the tubing to the surface for storage in tanks. To secure eicient pump operation it is important to maintain gas control in the vicinityl of the pump at the producing formation. Gas entering the pump with the oil can cause serious loss of etliciency and, at times, may even prevent operation of the valves within the pump. This diculty, due to the presence of free gas between the valves of the pump, may be prevented or alleviated by removing lthe rubber packer in the annulus to permit an escape passage for the troublesome gas. The gas is then tapped Vfrom the annulus at the surface to be disposed of as desired. Thus, the oil well illustration represents a situation wherein the temporary rubber spacer functions as a service barrier or seal. A still further example is where a mass, such as machinery, is to be lowered or raised to dicultly accessible places by means of a hoist, crane and the like. A temporary rubbery spacer, molded to the desired shape such as dove-tail, barbell, etc., is the connecting link between the mass to be transported and the hoisting means. In this particular situation, the temporary rubber spacer undergoes extensive stress as there is a force continually tending to rupture the spacer. =In the preceding illustrations it is readily apparent that the manual or physical removal of the rubber spacer may become a tedious and time-consuming and expensive manipulation.l 'The novel rubber spacer of my invention overcomes, in the main, these diiculties.

Patented Aug. 11, 1959 ICC The following therefore, are objects of the invention:

An object of this invention is to provide an improved rubbery spacer.

Another object is to provide an improved rubbery spacer which may be chemically disposed of in situ.

Another object is to provide a novel rubbery spacer which serves as a seal in oil wells.

A still further object is the manufacture of a novel rubbery spacer to serve as a temporary member in a system or machine wherein its removal when the situa` tion arises may be effected by ignition or burning of the' spacer in situ.

A further object is to provide a disposable article of manufacture undergoing continual compressive stress or extensive stress during its use as a temporary member in a system.

A yet further object is to provide a disposable rubber spacer which functions as a temporary service barrier in a system.

Other and further objects of this invention will be apparent to those skilled in the art upon study of the accompanying disclosure.

The novel rubbery spacer of this invention is composited with components hereinafter described so that the removal or disposal of the spacer is accomplished merely by raising its temperature to the combustion temperature,'such as ignition by an electrical squib, a torch, a fuse, or the' like, and thus, burning the spacer in situ.

The term spacer in this invention designates a seal, packer, support, washer, ball'valve, connecting link, and the like. Artisans skilled in the art are familiar with such terminology and with their application and use in the various fields. i

The spacer of my invention comprises predominantly a mixture of rubber and an voxidant wherein the rubber is in the continuous phase. The rubber component may be natural or synthetic together with its appropriate compounding ingredients. It is only necessary that the rubber have such a Mooney value that it can be worked so that an oxidant can be blended therewith. Rubbers with Mooney (ML-4) values upto '100 are applicable although it is preferable to have a Mooney value in the range of from about l0 to about 40.

The synthetic rubbers can be prepared in any suitable polymerization system, such as emulsion, bulk, or suspension systems. To illustrate, an emulsion polymerization .system aan. be used te prepare homopolymers or copolymersgf .conjugated f olsns or copolymers of coniugated ,diQlenS with other monomeric Compounds. The conjugated d iolens which are applicable include 1,3- butadiene, isoprene, Vchlortylgnrene, 2,3-dimethyl-l,3buta diene, methylpentadiene, piperylene, and others. The conjugated vdienes of 4 to 6 carbon atoms are preferred, althoughdienes -o f more than 6 carbon atoms can be used as well as the various alkoxy, such as methoxy and ethoxy, and cyano derivatives. Monomeric substances capable of copolymeriyzng with the conjugated dienes are styrene, a-methylstyrene, acrylonitri1e,vand the vinylpyridines, i.e., v`2-vinylpyridine, 2,5-divinylpyridine, 2- methyl-S-Vinylpyridine, B-ethyl-S-vinylpyridine, and others. Any initiatorl system can be used, such as the iron pyrophosphate-hydroperoxide, either sugar-free or containing sugar; the sulfoxylate recipe; the persulfate recipe,l and the like. Any suitable emulsifier such as fatty orV iosin acid-soaps can be used. Conventional short stops, i.e., t-butylhydroquinone, 2,4-dinitrochlorobenzene, water-"solubledithiocarbarriates, may be employed as well as otheringrefdients ,such as antioxidants. The emulsion polymerization temperature is generally in the range of -40 lto 140 F. The treatment of crude natural rubber is too well-known to the art to warrant further discussion thereof.

Regardless of the source of the rubber, as stated previously, it is only necessary that the rubber have such a Mooney value that it can be worked so that the oxidant can be blanded therewith. Any suitable oxidant, such as ammonium nitrate, ammonium perchlorate, Ypotassium perchlorate, potassium nitrate, or mixtures thereof, and the like may be employed. The oxidant and rubber can be mixed in any manner known in the art, such as by a dispersion blade mixer.

The composition of the rubber spacer of my invention consists essentially of 50-85 or more parts of oxidant per 100 parts by weight of rubber binder-oxidant blend. The rubber binder comprises raw rubber, carbon black, plasticizer, antioxidant, vulcanizing agent and other compounding ingredients as desired, The rubber binder is subsequently mixed or blended with the oxidant; the blend possessing a. consistency which can be molded to the desired shape by injection molding, extrusion molding, or other molding processes known to the art. Heat treating the molded article, i.e., spacer, at a temperature in the range from about 70 to aboutf250 F., preferably from about 140 to about .180? F., and for a period of time between about 3 hours to about 7 days follows, thus permanently setting or freezing the shape of the spacer.

An oil resistant rubber can be made from Ythe following emulsion polymerization recipe. i

The emulsion polymerization is carried at a temperature of approximately 25 C. for a period of about 15 hours. After shortstopping and removal of unreacted monomers the polymer is recovered from the latex in a conventional manner.

To 100 parts by weight of the synthetic rubber produced above are added the following materials to produce the rubber binder.

Ingredient: Parts by weight Synthetic rubber 100 Carbon black 65 Zinc oxide 5 Dibutyl phthalate 10 Philcure-l13 1 1.5 Sulfur 2 Stearic acid l Phenyl--naphthylamine 3 1 N,N-dimethyl-S-tert-butylsulfenyl dithocarbamate.

The synthetic rubberv and carbon black are masterbatched and subsequently there is added to the masterbatch the remaining ingredients listed above. To this mixture (the components of which now form the rubber binder) is added 75 parts of ammonium nitrate per 25 parts by weight of the rubber binder. Substantial uniform distribution of the entire mix can be obtained in a Baker- Perkins dispersion mixer. The rubber binder-oxidant blend is molded to the desired shape and cured 48 hours at 170 F.

A molded and cured rubber binder-ammonium nitrate blend consisting vof 50 parts by weight of binder per 50 parts by weight-of ammonium nitrate will vignite when it oxidant incorporated into the blend. The ultimate use of the shaped and cured rubber binder-oxidant blend will, in a number of instances, govern the choice of the synthetic rubber component in the blend. For example, in a situation where my novel packer is exposed to hydrocarbons, the synthetic rubber component must be oil resistant, and thus, the use of, for example, the acryloniytrile copolymers is desired.

The specification is accompanied by a drawing disclosing a specific embodiment of the application of my novel rubbery spacer. The drawing is merely illustrative and is not to be construed as limiting the scope of the invention.

The drawing is a schematic View of a typical oil-well.

In the drawing, the numeral 1 indicates the surface casing set and cemented. This casing is to protect fresh water supplies near the surface, prevent vthe unconsolidated formations from caving and provide a means of controlling the flow of drilling Huid. Within the surface casing is oil-string casing 2 also set and cemented. The oil-string casing is not ordinarily set in a well until it has demonstrated that it is likely to be a producer. There are generally other casings, such as the intermediate casing, which are not shown in the simplified drawing. The nal step in preparing the piping for a producing well is running in the tubing 3 to the bottom of the well or pay zone 4 so that an annular chamber is formed between the tubing 3 and the oil-string casing 2. Packer 5 comprising 75 parts by weight of ammonium nitrate and 25 parts by weight of acrylonitrile-butadiene blend prepared in the manner explained above, is fitted in the annulus at the desired depth, and is connected to electric source 6. An electric squib may either be incorporated into the packer or be adjacent thereto. Within the tubing is reciprocating pump 7, connected by means of sucker rods 8 Ito the pump unit 9 on the surface. The pump technique is ernployed when the oil formation lacks the necessary pressure to ow naturally. As the piston within reciprocating pump 7 is moved upward, ball valve 11 is opened and fluid from pay zone 4 is admitted while ball valve 12 remains in a closed position. The downward stroke of the piston, closes ball valve 11 and opens ball valve 12 wherein the fluid enters the cavityv above the reciprocating pump. In this continuous fashion, the fluid is lifted to the surface. However, gas entering the reciprocating pump along with the fluid may lodge between the ball valves, thus decreasing the efficiency of the pump. The gas within the pump is merely compressed and expanded by the action of the pump, and little fluid is thereby lifted through the tubing to the surface. When such a situation arises it may be necessary to remove the packer to permit the gaseous buildup at the well bottom to escape through the annular chamber. The pulling of the packer is a tedious, expensive, time-consuming procedure. With the novel packer of my invention, the packer is merely burned or ignited 'm situ by setting off the electrical squib by turning on electric source 6. The packer can be also ignited by other means, such as lowering a torch through the tubing to a point adjacent to the packer. The metal tubing is heated at that point whereby the packer will ignite and burn when the ignition temperature is reached. Thus, the gas can escape upward through the unimpeded annulus to the surface to be utilized or discarded, as desired. By the above expedient'the gas can eventually be worked out of the reciprocating pump.

The preparation of a typical synthetic rubber, the cornpounding thereof, followed by blending with an oxidant,

is heated to a temperature of approximately '450 F.

prior to molding and curing the blend, has been set out in particular detail. The application of the molded and cured blend as a packer in an oil well operation has also been set forth. It is not my intent to be limited to this speciiic embodiment. It is desirable that the invention be practiced with a natural or synthetic rubber which has 'such a Mooney value, i.e., up to 100, that it can be'worked so that an oxidant can be blended therewith. It will be apparent to those skilled in the art that various modifications and applications of this invention can be made upon study of the accompanying disclosure without departing from the spirit and scope of the said disclosure.

I claim:

1. As an article of manufacture an oil well packer having an annular resilient seal member consisting essentially of a composition comprising a rubbery binder selected from the group consisting of natural rubber and synthetic, conjugated diene polymer :and sufficient oxidant in admixture therewith to supply the oxygen necessary for combustion with substantial decomposition of said packer, thereby rendering said packer both ignitible and self-sustaining in combustion even in the absence of any external source of oxygen.

2. As an article of manufacture an oil well packer having an annular resilient seal member consisting essentially of a composition comprising a mixture of rubbery binder selected from the group consisting of natural rubber and synthetic, conjugated diene polymer and from 50 to 85 parts by weight per 100 parts olf mixture of oxidant selected from the group consisting of ammonium nitrate, ammonium perchlorate, potassium nitrate, potassium perchlorate, and mixtures thereof, thereby rendering said packer both ignitible and self-sustaining in combustion to substantial decomposition thereof even in the absence of any external source of oxygen.

3. An article of manufacture according to claim 2 wherein said rubbery binder is a copolymer of butadiene and acrylonitrile.

4. In an operation wherein the application of a force is adapted to be temporarily restrained and subsequently released, the improved method which comprises positioning in the path of said force a body consisting essentially of a composition comprising a rubbery binder selected from the group consisting of natural rubber and synthetic, conjugated diene polymer and sufiicient oxidant in admixture therewith to supply the oxygen necessary for combustion with substantial decomposition of said body, thereby rendering said composition both ignitible and self-sustaining in combustion even in the absence of any external source of oxygen, and igniting said body in situ so that said body substantially decomposes.

5. A method of packing oit and subsequently removing the packing material from an oil well which comprises positioning in said Well packing material comprising a rubbery binder selected from the group consisting of natural rubber and synthetic, conjugated diene polymer and sufficient oxidant in admixture therewith to supply the oxygen necessary for combustion with substantial decomposition of said packing material, thereby rendering said material both ignitible and self-sustaining in combustion even in the absence of any external source of oxygen, and igniting said packing material in situ so that said packing material substantially decomposes.

6. A method of packing oi and subsequently removing the packing material from an oil well which comprises positioning in said well packing material comprising a mixture of rubbery binder selected from the `group consistinlg of natural rubber and synthetic, conjugated diene polymer and from to 85 parts by weight per 100 parts of mixture of oxidant selected from the group consisting of ammonium nitrate, ammonium perchlorate, potassium perchlorate, potassium nitrate, and mixtures thereof, thereby rendering said packing material both ignitible and self-sustaining in combustion to the substantial decomposition thereof even in the absence of any external source of oxygen, and igniting said packing material in situ so that said packing material substantially decomposes.

7. A method according to claim 6 wherein said rubbery binder is a rubber having a Mooney (ML-4) value in the range of about 10 to 40.

8. The method of claim 4 wherein the body comprises from about 50 to about 15 parts of a rubbery binder possessing a Mooney value not greater than and from about 50 to about 85 parts of an oxidant.

References Cited in the file of this patent UNITED STATES PATENTS 1,249,180 Ostromislensky Dec. 4, 1917 2,138,156 Halliburton NOV. 29, 1938 2,291,862 Bailey Aug. 4, 1942 2,624,603 Sweet Ian. 6, 1953

Claims

4. IN AN OPERATION WHEREIN THE APPLICATION OF A FORCE IS ADPATED TO BE TEMPORARILY RESTRAINED AND SUBSEQUENTLY RELEASED, THE IMPROVED METHOD WHICH COMPRISES POSITIONING IN THE PATH OF SAID FORCE A BODY CONSISTING ESSENTIALLY OF A COMPOSITION COMPRISING A RUBBERY BINDER SELECTED FROM THE GROUP CONSISTING OF NATURAL RUBBER AND SYNTHETIC, CONJUGATED DIENE POLYMER AND SUFFICIENT OXIDANT IN ADMIXTURE THEREWITH TO SUPPLY THE OXYGEN NECESSARY FOR CUMBUSTION WITH SUBSTANTIAL DECOMPOSITION OF SAID BODY, THEREBY RENDERING SAID COMPOSITION BOTH IGNITIBLE AND SELF-SUSTAINING IN COMBUSTION EVEN IN THE ABSENCE OF ANY EXTERNAL SOURCE OF OXYGEN, AND IGNITING SAID BODY IN SITU SO THAT SAID BODY SUBSTANTIALLY DECOMPOSES.