POLYMER ARTICLE OF MANUFACTURE

Abstract: A solid polymeric body comprising a polymer matrix containing a substantially water-insoluble reagent leachable into a substantially hydrocarbon liquid environment, said matrix being reagent permeative and the said body preferably having a softening point substantially above that of the temperature of the liquid fluid environment in which it is to be employed is useful for the introduction of an additive reagent into a substantially liquid hydrocarbon such as crude and refined oils.

Description: POLYMER ARTICLE OF MANUFACTURE Field of the Invention This invention relates to a polymeric body useful for introduction of an additive into a substan- tially hydrocarbon liquid. More particularly this inven- tion relates to a bead containing an additive which is leachable into an oleaginous hydrocarbon liquid (both crude and refined) and the method of utilizing the bead to introduce the additive in useful amounts into the liquid hydrocarbon. Background of the Invention The recovery of oil and gas from underground geological formations is of great importance in modern society which uses vast amounts of fossil fuels for its essential energy. The individual well productivity declines over a period of time because of a number of factors including changes in reservoir fluid charac- teristics, depletion of reservoir energy, decreasing permeability of the formation to the oil, the gradual dissipation of the expanding pressure transient, contami- nation of the well bore, reduced permeability of the oil through the region immediately surrounding the well bore and reduction of the internal diameter of the well pipe. The response to the declining productivity was the development of numerous techniques which has become collectively known as well workover and stimulation. The concept of fracturing or formation breakdown has been recognized to play a very important role in the applica- tion of these oil production enhancement techniques including stimulation, acidizing, water injection and cementing of the formation. Hydraulic fracturing has found wide usage as a well stimulation procedure for creating deep-penetrating fractures (both horizontal and vertical) that provide high capacity channels for flow from deep within the producing formation to the well as well as for overcoming damaged matrix permeability surrounding a wellbore. In order to produce gas or liquids from a well at a higher rate following a hydraulic fracturing treatment, the reservoir must contain enough fluids in place and the formation must not have regions of severe permeability reduction partic- ularly in regions adjacent to the well. Early experi- mental work in shallow wells demonstrated that a hydraulically formed fracture tends to heal - that is, to lose its fluid carrying capacity after the parting pressure is released - unless the fracture is propped. Typical propping agents for retaining the integrity of the fractures are nutshells, plastic beads, aluminum spacers, glass beads, sand and urea prills. Proppants thus provide a means for meeting the objective of the fracturing which is to increase the well production by preventing collapse of the formation and resultant decrease in fluid permeability. Another cause of declining well production is caused by paraffin deposition from the crude oil onto the inner walls of the production tubing and equipment. Paraffin is a reservoir produced group of straight-chain alkanes that contain more than 15 to more than 80 carbon atoms. The melting point of the paraffin increases as the size of the molecule increases. Paraffin is deposited in the form of crystalline solids which may collect on the interior of the tubing and flowlines, slowly choking off production. Paraffin deposits have also caused the breaking of pump rods. In some cases, paraffin deposits have caused plugging of formations during stimulation treatments. Paraffin has also been blamed for the difficulty in pumping crude oil at cool temperatures. One method of handling paraffin deposition is to mechanically remove the paraffin. There are several mechanical methods for removing deposited paraffin from tubing,, flαwlines and pipelines which include rod scrapers, free-floating pistons, etc. The major advantage of mechanically removing paraffin is that positive cleaning is assured, however, it is limited due to time and equipment involved, costly and has the danger and difficulty inherent in retrieving tools lost in the hole during the cleaning operation. Other methods of cleaning include: (1) thermal methods, using bottomhole heaters, circulation of hot oil, water or steam, and heat- liberating chemicals; and, chemical including the use of paraffin solvents, dispersants and detergents and crystal modifiers whereby the latter prevents paraffin deposition by disrupting the nucleation, agglomeration and/or deposition of the paraffin crystals environment. At present the chemical reagent is injected into the desired location but it can be difficult to supply it uniformly to the optimum location, for instance in the permeable, oil bearing, mineral formation. Also it is necessary to inject the reagent continuously or repeatedly since it is soluble in the produced fluid and so is rapidly removed from the point of injection. As indicated it is known to introduce reagents downhole during fracturing and other well stimulation processes. Traditionally this is done by forcing a solu- tion of the reagent down the hole and into the formation, whereupon it becomes absorbed onto the formation and is released slowly from it. Unfortunately the rate of release is variable and generally is quite fast. It is known to force beads of ethylene-viny1 acetate copolymers into the formation, but they are generally too large to get into the fractures formed in the formation and smaller beads would dissolve too rapidly. Also the beads are rather soft. Another approach to overcoming the paraffin deposition in the recovery of crude oil is by adding to the oil a polymer having pendant polar and non-polar moieties, such as a partially hydrolyzed ethylene-viny 1 OMPI acetate copolymer, whereby the deposition of wax from the oil is inhibited (see U.S. Patent 3,693,720 wherein the inhibitor is added to the crude petroleum oil before the temperature of said oil decreases to a wax-deposition temperature). It is known from British Patent Specification 1,290,554 to inhibit scale formation downhole by supplying downhole a solid linear carboxylic polymer having low molecular weight and in which the carboxylic groups are neutralized by an alkaline earth or other insolubilizing cation to an extent such that the polymer has a controlled low solubility in water. It is stated in that specifica- tion that water soluble scale inhibitors may also be supplied downhole with the substantially insoluble polymer. It is an object of this invention to provide an article and its use to enhance the production of hydro- carbons from geological reservoirs, more particularly from fractured formations. It has been an additional object to devise a composition for providing controlled release of a reagent downhole, in a pipelin-e, in other oil-containing environ- ents or fluids. Summary of the Invention It has been discovered that it is possible to provide for the introduction of an additive reagent into a liquid hydrocarbon by providing solid polymeric bodies each comprising a polymeric matrix containing a substan- tially water insoluble reagent such as a wax crystal modifier, demulsifier, scale inhibitor, corrosion inhibitor, biocide, ashless dispersant, antioxidant and mixtures thereof. These bodies are, in use, positioned at a location where it is desired to release the reagent into the substantially hydrocarbon fluid and, upon contact with fluid in this location, active reagent is released into the fluid. Thus in accordance with this invention there is provided a solid polymeric body comprising a polymer matrix containing a substantially water-insoluble reagent leachable into a substantially hydrocarbon liquid environment, said matrix being reagent permeative and the said body preferably having a softening point substan- tially above that of the temperature of the liquid fluid environment in which it is to be employed and optimally having a leach rate in which fifty percent of the reagent is leached from the bead in from 3 months to 3 years by the fluid environment. The object of this invention has been realized in specific form by beads comprising a copoly eric matrix of methylmethacrylate and methacrylic acid containing the beheny ' l half ester of a C2 - 28 alkenyl succinic anhydride polymer and having a diameter ranging from 0.2 to 1 mm. Such beads when introduced downhole in a hydraulic frac- turing operation were found to inhibit paraffin wax deposition. Pet-ailed Description of the Invention Each of the solid polymeric bodies may consist solely of a polymeric matrix containing the reagent or may contain a region, generally an outer region, of polymeric material having a lower rate of reagent permeation than that of the interior region and substantially free of reagent. The polymer of such an outer shell may be of the same material as the matrix or may be different, and will be selected having regard to the release properties required from the polymeric bodies. Matrix containing reagent may be of uniform composition throughout its body or its composition may vary, for instance having a different polymer composition in its outermost portions from its core portion. By appropriate selection of the polymeric materials for forming -the bodies and the distribution of reagent within the bodies it is possible 1 to control the rate and duration of release of reagent 2 into the fluid while retaining the physical (structural) 3 integrity of the polymeric matrix 4 It is this polymeric property of reagent 5 permeativity which makes possible the transfer of the 6 reagent from the body into the substantially hydrocarbon 7 liquid in contact with the surface of the body. During 8 and after the leaching of the reagent from the reagent 9 permeative matrix of the body, the polymeric matrix 10 retains its structural integrity which is in marked 11 contrast to the approach taught in Egypt. J. Pharm. Sci., 12 19 No. 1-4, pages 143-62, 1980 in an article by A. Kassem 13 et al entitled Formulation and Evaluation of Controlled 14 Dissolution Phenobarbitone Macromolecular Products 15 Employing In Situ Suspension Polymerization With Methyl- 16 methacry late wherein the reagent coated beads were 17 compressed into a body which upon reagent dissolution in 18 the physiological aqueous fluids broke down the body into 19 its component beads thus fully destroying the structural 20 integrity of the compressed body. 21 The polymeric bodies are preferably particles. 22 The particle size is generally at least 10 microns and 23 preferably at least 50, and usually at least 100, microns 24 since small particles can be difficult to handle and to 25 position permanently in their desired environment. The 26 particle size is generally less than 2 mm and preferably 27 less than 1 mm, since large particles also may be diffi- 28 cult to position in their desired environment. Best 29 results are generally obtained with a particle size of 30 from 50 microns to 1 mm. The particles may have irregular 31 shape and sizes, for instance as a result of having been 32 made by crushing, but preferably the particles are of 33 substantially spherical or other uniform shape. 34 When being used in fracturing, the particles 35 preferably have a size and hardness and/or resistance to 36 flow such that they can be used in sand packing and will 37 not be significantly degraded by the sand. The particle ...PI size distribution will be selected so that a pack of controlled permeability to fluid flow is formed and such that the particles have a controlled leach rate as set forth earlier. The reagent must be substantially water insoluble, and so must partition into an organic phase of substantially water-insoluble poly erizable monomer or monomer mixture in preference to a water phase. The reagent may be in its active form or it may be in a blocked water-insoluble form from which an active form may be released during use and that may be water soluble. The reagent may be dissolved in the polymeric matrix but preferably at least some, and generally substantially all, of the reagent is dispersed in the matrix. The softening point of the reagent should be above ambient temperatures encountered in use. The reagent may be any active reagent that is usefully administered to and is soluble in refined or crude oil, or that is any blocked reagent that is water insoluble but which, upon contact with water or oil, will release a water soluble or water insoluble reagent that is useful in the substantially hydrocarbon fluid. The reagents are usefully selected from wax crystal modifiers, demuls i fiers , scale inhibitors, corrosion inhibitors, biocides, dispersants, antioxidants and mixtures thereof. (a) Wax Crystal Modifiers These reagents, usefully introduced in at least a wax deposit inhibiting amount to the refined and crude oil, are represented by oil-soluble polymers having pendant polar and non-polar moieties and oil-soluble polymeric materials having long linear side chains. The oil-soluble copolymers having pendant polar and non-polar moieties are represented by the formula C- -CH 2 CHR-^ m - ( --CH2CHX^-p-(-.CH2CHY- - τr .] q wherein X is a non-polar moiety, Y is a polar moiety, R is hydrogen, an alkyl, aryl, aralkyl, or alkaryl moiety, m is 1.5-3, n is 0.1-0.8, p is 0.01-0.5, m/(m+n+p) is 0.65-0.97, p/(n+p) is 0.1-0.85, q is 2 to 500, and the molecular weight * w of said polymer is 500-100,000. The above polymer may typically be a polymer having a molecular weight R w of 500-100,000, preferably 1,000-10,000, commonly 1,500-4,000, say 2,000, and characterized by a long straight backbone chain on which there may be pendant moieties X and Y. In the above copolymer, the moiety —(— CH2CHR—.— m may be derived from an alpha-olefin including ethylene, propylene, butene-1, styrene, 3-pheny1-1-propene , octene-1 , etc. Preferred alpha- olefins may be the 2-C30 alpha-olefins and most preferred is ethylene. When the alpha olefin is propylene, the formula —(—CH 2 CHR—— m may be CH 3 I - —CH2 CH— )— m in which R is -CH3. When the alpha olefin is ethylene, the formula may be —(— CH2-CH2—_"— m « The carbon atoms may bear insert substituents (i.e. in place of the hydrogen atoms) including alkyl, cycloalkyl, aryl, alkaryl, aralkyl, etc., moieties. In the above copolymer, the moiety —(— CH2CHX— )— n may b.e derived from an alpha-olefin which bears non-polar moiety X. The non-polar X moiety may be characterized by the fact that it does not contain a hydrogen atom active in the Zerewitinoff test for active hydrogen. Typically, the non-polar moiety will contain atoms of carbon, nitrogen, sulphur, phosphorous, boron, oxygen, etc. The polar moiety Y may be a moiety con- taining carbon, oxygen, sulphur, nitrogen, phosphorous boron or their congeners. The Y moiety contains a hydro- gen atom which is capable of participating in hydrogen bonding. A typically useful wax crystal modifier is a OMPI (b) Demulsifiers These reagents which can be introduced into a fractured subterranean oil bearing formation in accordance with this invention are usefully introduced to inhibit emulsifica- tion of the crude oil with formation water, water flood injection water and/or water introduced by such processes as steam stimulation. These oil-soluble reagents include polyoxyalkylene ether and polyalkylene surfactants formed from the alkoxylation of hydrocarbon soluble alkyl phenols, phenolic resins, alcohols, glycols, amines, organic acids, carbohydrates, mercaptans, and partial esters of polybasic acids. (c) Scale Inhibitors Since scale inhibitors are water soluble each is intro- duced into a fractured subterranean formation in accor- dance with this Invention as the reagent in a blocked form such that the reagent upon contact with water, as by leaching from the polymeric matrix, is converted into a water soluble active form, e.g. as a result of hydrolysis or ion exchange. Suitable blocked forms are fatty acid esters and salts. Typical examples of blocked scale inhibitors are the salts formed by the reaction of hydrophobic amines with low molecular weight pα lycarboxylic acids or pαly- phosphonic acids, e.g. a tri(Cg-C-|g alkyl) ammonium salt of: polyacryl-ic acid having a M w of from 1,000 to 5,000; or dihexylene triamino pentakis methylene phos- phonic acid. It is believed that the latter reagent also has activity as a corrosion inhibitor. (d) ^ C ^B o_ M r VM^ r ^^ o ^ s ^^ i ^^ o ^B^ n ^^B ___I__ B _n_ BaB h_____i_ a _b__ a __i____t__ B _o B __ a r aHa _s B __ a __ ^ _a____n a __ B d αa _ Baa _ a B_ B __ a i M _o____c ιa^ _i a _ B _d_ αaa e B ___s__ H Useful reagents which have the property of corrosion inhibition and/or biocidal activity include both oil- soluble and water-soluble materials. The latter must be incorporated into the polymeric matrix in blocked form. 1 Typical examples of oil soluble corrosion 2 inhibitors and/or biocides are amines, dia ines, fatty 3 amines, polyamines, alkoxylated amines, hydrogenated fatty 4 amines, amides, fatty acid amides, imidazolines, and 5 trimer acids. 6 Typical examples of water soluble corrosion 7 inhibitors and/or biocides are quaternary amines and 8 quaternized imidazolines each of which can be individually 9 blocked by reaction with oleophilic fatty acids to form 10 water insoluble salts whereby it becomes useful in the 11 present invention. 12 The reagents may also be materials of value in 13 fuels and lubricating oils, for instance ashless disper- 14 sants or antio idants. A filter bed through which such 15 fluids or oils pass may contain or consist of the parti- lδcles containing such reagents. 17 (e) Ashless Dispersants 18 As used herein, the terminology "ashless dispersant" is 19 intended to describe the now well-known class of non- 20 metal-containing oil-soluble polymeric additives or the 21 acyl derivatives of relatively high molecular weight 22 carboxylic acids which are capable of dispersing contami- 23 nants and the like in hydrocarbons such as lubricating 24 oils. The carboxylic acids may be mono- or polycarboxy1ic 25 acids and are generally characterized by substantially 26 hydrocarbon constituents containing an average of 50 to 27250 aliphatic carbon atoms. 28 A preferred class of ashless dispersants are the 29 nitrogen-containing dispersant additives which include 30 mineral oil-soluble salts, amides and esters made from 31 high molecular weight mono- and dicarboxylic acids (and 32 where they exist the corresponding acid anhydrides) and 3 various amines of nitrogen-containing materials having 4 amino nitrogen or heterocyclic nitrogen and at least one 5 amido or hydroxy group capable of salt, amide, imide or 6 ester formation. Usually, these dispersants are made by 7 condensing a mono-carboxylic acid or a dicarboxylic acid f O PI or anhydride, preferably a succinic acid producing material such as alkenyl succinic anhydride, with an amine or alkylene polyamine. Usually, the molar ratio of acid or anhydride to amine is between 1:1 to 5:1. Primarily because of its ready availability and low cost, the hydrocarbon portion of the mono-, or dicarboxylic acid or anhydride is preferably derived from a polymer of a C2 to C5 monoolefin, said polymer mono- olefin generally having between 50 and 250 carbon atoms. A particularly preferred polymer is polyisobutylene. Polyalkyleneamines are usually used to make the non-metal-containing dispersant. These polyalkyleneamines include diethylenetriamine , tetraethylenepentamine , dipropylenetr iamine , octaethylenenonamine , and tetra- propylenepentamine. Highly useful mixtures of alkylene polyamines approximating tetraethylene pentamine are commercially available. Representative dispersants are formed by reacting about one molar amount of an oil-soluble poly- isobutenyl succinic anhydride with from about one to about two molar amounts of tetraethylene pentamine or with from about 0.5 to 1 moles of a polyol, e.g. pentaerythritol. It is possible to modify the ashless dispersants generally by the addition of metals such as boron in order to enhance the dispersancy of the additive. (g) Antioxidants As used herein, antioxidants are oil-soluble oxidation inhibitors and generally represented by the additives for lubricating oils which include phenols, amines, sul- phurized phenols, alkyl phenothiazines, and zinc dihydro- carbyl phosphorodith iαates , e.g. zinc di-n-propyl dithiophosphate. Polymeric Body The polymeric matrix is reagent permeative and preferably has a softening point as measured by a temperature-graded hot bar of above 30°C and most preferably is above 60°C, often up to 120°C. The combination of the reagent and the polymeric matrix must be such that the reagent is released into surrounding fluid at the desired time and rate either as a result of the fluid permeating through the matrix to dissolve the reagent or as a result of the reagent permeating through the matrix to dissolve into the fluid, or both. amounts of reagent and so the amount is generally not more than 5058, and usually not more than 308, by weight of the total body. The preferred reagent amount is usually 10 to 3050 by weight of the total body. The invention has widely diverse applications since it makes passible a controlled release of reagent into liquids in a uniform manner and over extended time periods. It makes possible the release of certain reagents from previously non- or difficulty accessible and diverse points such as in an oil bearing mineral formation one or more miles underground and in the flow path of a circulating engine lubricant. This invention provides a method for the controlled introduction of a reagent into a substantially hydrocarbon liquid, generally a circulating liquid, which method comprises the steps of: (a) placing solid polymeric bodies, each body comprising a polymeric matrix containing at least one substantially water insoluble reagent in a liquid, generally flowing, substantiall hydrocarbon fluid; and (b) leaching out said reagent from said bodies at a controlled and predetermined rate into said liquid fluid, said fluid preferably containing oil. In a preferred manner the invention provides a method of recovering a crude petroleum oil containing waxy components, from a reservoir wherein the oil is at a temperature above its wax deposition temperature which comprises: a. passing a portion of said crude petroleum oil from said reservoir to a first central collection point, i.e. the well bore; b. passing said oil from said first central collection point to a second collection point, i.e. the well head at a temperature below the wax deposition temperature of said oil whereby the temperature of said oil decreases and passes through a wax- ' .osition temperature at which the waxy components |in to precipitate and to deposit on surfaces with Lch said oil comes in contact as it passes to said :ond collection point; Lon. This is often a hydrophilic polymer that is swellable in, and usually soluble in, the aqueous medium. The hydrophilic dispersing stabilizer may be a naturally occurring or modified naturally occurring polymer, such as a hydroxyethyl cellulose, or a synthetic water soluble polymer, for instance polyvinyl alcohol or polyethylene oxide but preferably is a synthetic carboxylic acid OMPI containing polymer, most preferably pαlyacrylic acid having a molecular weight in the range 1 million to 10 million. The amount is generally 0.2 to 5% weight of the water. In order to obtain uniform and fine distribution of the reagent in the polymeric matrix, it is necessary for the reagent to be monomer-wetting rather than water- wetting and preferably the reagent is in liquid form during polymeriza ion of the matrix. It could be intro- duced as a solution in toluene or other suitable organic solvent but this would have the disadvantage of incor- porating solvent in the matrix. Preferably therefore the reagent is one that dissolves into the polymerizable material, if necessary as a result of being heated. For instance it may be insoluble in the polymerizable material at ambient temperatures but may become soluble upon heating to 'a temperature between 50 and 80°C, in which event the dispersion of the particles of reagent and liquid polymerizable material is formed at such a temperature. The elevated temperature may be such that the reagent is then truly molten or may be such as to promote solubility of the reagent in the polymerizable material. Preferably a homogeneous blend Is formed of the reagent and the monomer or monomers, dispersed into the aqueous medium by stirring and polymerization is initiated by using an oil soluble thermal initiator. The following are examples of the invention. EXAMPLE 1 The behenyl half ester of a 2 -C28 alkenyl succinic anhydride polymer produced generally according to the procedure set forth for preparation of Polymer B disclosed in United States Patent 3,854,893 was supplied as a solution in toluene, and this solvent was evaporated to leave a waxy solid. This wax, i.e. the reagent, was insoluble in methyl methacrylate monomers at temperatures up to 50°C. A monomer solution containing the wax reagent was formed of 85 g methyl methacrylate, 5 g methacrylic acid and 10 g of the wax by heating all to 65°C, at which temperature the wax dissolved into the monomers. The resultant solution was then dispersed in 200 g water containing 3 g polyacrylic acid (molecular weight about 2 million) as a dispersing stabilizer of the monomer drop- lets during polymerization in a one litre enclosed vessel provided with a stirrer for controlled agitation of the contents within the vessel. Under constant agitation 1 g of azodiisobutyronitrile as the polymerization inhibitor was added. Suspension polymerization was continued with constant agitation for two hours after which time the product within the vessel consisted of a suspension of small polymeric beads in the aqueous medium. These beads were separated from the aqueous medium, washed and dried to give free flowing beads of from 0.2 to 1 mm in diameter with 1QS. by weight of the waxy ester polymer reagent dispersed in the polymeric matrix. Since the behenyl ester wax reagent is very soluble in hexane, to demonstrate the retardation of solubility by the invention the produced beads were stirred in hexane at 35°C and the amount of wax released recorded. The following results were obtained. % of Total Wax Released Time Hours at 35 ' ' C 40 1 42 2 45 3 49 4 53 5 EXAMPLE 2 W Whheenn tthhee above process was repeated using 10 g wax reagent (as above described) , 5 g acrylic acid, 5 g methacrylic acid and 80 g methyl methacrylate followed by neutralization with sodium hydroxide dispersion, the beads have a shell containing a high proportion of sodium poly- acrylate and have slower release properties compared to 1 the release properties of the beads of Example 1 when the 2 polymerizate dispersion was similarly neutralized. In 3 particular, after 5 hours at 35 β C in hexane as in Example 41, only 2558 of the wax was released. 5 EXAMPLE 3 6 To produce a polymeric body according to this 7 invention containing a leachable scale inhibitor, the 8 polymerization mixture will be 90g of methyl methacrylate, 9 and 10g tri Cg-Cιo alkyl) ammonium lOsalt of a poly(acrylic acid) having a flw of 1,000 to 115,000. The polymerization mixture is to be polymerized 12 under the conditions of Example 1. 13 EXAMPLE 4 14 In order to produce a polymeric body according 15 to th.is invention containing a leachable corrosion 16 inhibitor reagent, " the procedure of Example 3 is to be 17 followed except that the 5g of methacrylic acid is 18 replaced with 5g of dimethylamiπoethyl acrylate, the 10g 19 of the ammonium salt is replaced with 10g of the equimolar 20reaction product of tall oil fatty acid and diethylene 21 triamine and the anionic dispersing stabilizer is changed 22to 3g of the methyl chloride quaternary salt of poly 23 (di-methylaminoacrylate) of about 1 million Mw. 24 EXAMPLE 5 25 in order to produce a polymeric body according 26 to this invention containing a leachable de ulsifier, the 27 procedure of Example 3 is followed except that the 28foHo ing monomer mixture is used: 65g methyl 29 methacrylate , 20g styrene, 5g methacrylic acid and 10g of 30an oxyalkylated phenol formaldehyde resin of 2000 flw 31 where the weight ration of ethylene oxide to propylene 32oxide to resin is 0.5:0.5:1.5. 33 EXAMPLE 6 34 in order to produce a polymeric body according 35to this invention containing a leachable ashless 36 dispersant , the procedure of Example 1 is followed except t h at t h e w ax i s r ep l ac e d w i t h t h e e q u im o l a r r e ac t i o n product o f pol y isobut eny 1 succinic anhydride having a Rw of about 900 and pentacrythritol . EXAMPLE 7 The effectiveness of the present invention in the inhibition of wax deposition from a crude oil was shown by comparison of the product of Example 1 with a solution of the reagent of Example 1 on a crude oil (in which the aforesaid reagent has shown measurable wax deposition inhibiting activity) using the following procedure. 0.03 weight parts of active ingredient was introduced into 100 weight parts of crude petroleum oil. The mixture was placed within a test cell containing a preweighed, removable standard water chilled deposition steel plate, a stirrer thermometer, and an electrical heater. The test cell was placed in an insulated bath together with an identical reference cell containing the reagent solution treated base crude oil. The temperature of the oils in both cells was maintained at 2° to 5.5°C. above the known cloud point temperature of the oil (as determined by ASTM D-97-57). The test was continued for 6 hours and then each deposition plate was removed, and weighed. The amount of wax deposit on each plate was for measurable activity the same. EXAMPLE OF USE The solid particles of the present invention can be used to inhibit paraffin deposition from waxy crude oils by placing them downhole with the proppant sand during the course of a fracturing operation. To effect the placement of the particles of the invention a fracturing operation is carried out as follows. A fracturing fluid is prepared by gelling a 2% solution of potassium chloride with hydroxy propyl guar cross linked with a transition metal complex. As the fluid is pumped downhole 8 lbs/1000 gals of 20-40 mesh sand mixed with 5% of the beads of the invention are added to serve as a proppant in the fractures formed in the OMPI producing formation. Pump pressure is increased above the fracture gradient of the rock formation and the fluid carries the proppant mixture into the fractures. The well is then shut in for 24 hours to allow the guar gel to degrade to a low viscosity solution. The well is allowed to flow back and the fracturing fluid is recovered leaving the proppant mixture of sand and polymer beads behind. As the produced oil flows through the proppant pack past the beads the wax deposition inhibitor slowly leaches out and deposition is inhibited in the well bore and the flow lines as the oil cools and production is maintained at a high level without wax blockage. As used herein % by weight is based on the total weight of the body, polymer composition, water or bead, respectively . ^ fREAi

Claims: WHAT IS CLAIMED IS: 1. A solid polymeric body comprising a polymer matrix containing a substantially water-insoluble reagent leachable into a substantially hydrocarbon liquid environment, said matrix being reagent permeative. 2. A body according to claim 1 having a softening point substantially above that of the temperature of the liquid substantially hydrocarbon environment in which it is to be employed. 3. A body according to claim 1 wherein said reagent is removed from within said matrix to outside of said body at a leach rate in which fifty percent of the reagent is leached from ' the body in from 3 months to 3 years by said environment. 4. A body according to claim 1 wherein said leachable reagent is at least one wax crystal modifier, de ulsifier, scale inhibitor, corrosion inhibitor, biocide, ashless dispersant, antioxidant and mixtures thereof. 5. A leachable body according to claim 1 wherein said matrix is a copolymer of methy lme hacry1ate and methacrylic acid and said reagent is the behenyl half ester of a C2 -C28 alkenyl succinic anhydride polymer. 6. A body according to claim 5 wherein said copolymer contains a proportion of a substantially hydro- philic comonomer. 7. A body according to claim 6 wherein said hydrophilic comonomer is acrylic acid. OMPI 8. A body according to claim 1 having a diameter ranging from 0.2 to 1 mm. 9. A body according to claim 1 having an outer region of polymeric material free of reagent. 10. A body according to claim 9 wherein said outer region is or a polymer material having a lower rate of reagent permeation than that of the interior region. 11. A body according to claim 8 wherein each particle has a size range of at least 50 microns and less than about 1 mm. 12. A body according to claim 1 wherein the polymeric matrix has a softening point temperature ranging upwards from 30°C. 13. A body according to claim 1 wherein the reagent is 10 to 30S. by weight of the total weight of the body. O.IPI

Inventors: MCDOUGALL LEE A, NEWLOVE JOHN C, STOCKWELL JOHN R, WALKER JOHN R, MCDOUGALL, LEE, A., NEWLOVE, JOHN, C., STOCKWELL, JOHN, R., WALKER, JOHN, R.
Applicants: EXXON RESEARCH ENGINEERING CO, EXXON RESEARCH & ENGINEERING COMPANY
Application year: 1984
Main classification: C09K3
IPC codes: A61K9, B01J13, C08F2, C09K8