Patent Grant
7741251
The present invention relates to well bore stabilization and, more particularly, to treatment fluids that may reduce the tendency of shales to swell and associated methods.
A treatment fluid may be used in a subterranean formation in a variety of ways. For example, a fluid may be used to drill a well bore in a subterranean formation, to stimulate a well bore in a subterranean formation, or to complete a well bore in a subterranean formation, as well as or for a number of other purposes. The process of drilling a well typically requires the use of a drilling fluid. A drilling fluid used in connection with drilling a well in a subterranean formation may comprise a number of fluids (gaseous or liquid) and mixtures of fluids and solids (e.g., as solid suspensions, mixtures and/or emulsions of liquids, gases and solids) used in operations to drill well bores into subterranean formations. Drilling fluids are used, inter alia, to cool the drill bit, to lubricate the rotating drill pipe to prevent it from sticking to the walls of the well bore, to prevent blowouts by serving as a hydrostatic head to counteract the sudden entrance into the well bore of high pressure formation fluids, and to remove drill cuttings from the well bore.
During the drilling of subterranean well bores, it is not uncommon to encounter strata comprising shales. As referred to herein, the term “shale” will be understood to mean materials such as certain types of clays (e.g., bentonite) and related subterranean materials that may “swell,” or increase in volume, when exposed to water. The shale may be problematic during drilling operations because, inter alia, of its tendency to swell when exposed to aqueous media, such as aqueous-based drilling fluids. Shale swelling may result in undesirable drilling conditions and undesirable interference with the drilling fluid. The increase in bulk volume of the shale associated with shale swelling may impede the removal of drill cuttings from beneath the drill bit, increase the friction between the drill string and the sides of the well bore, and inhibit the formation of a desirable filter cake on the formation. Shale swelling also may result in other problems, such as the loss of drilling fluid circulation or stuck pipe that may result in undesirable delays and expenses. Furthermore, shale swelling also may substantially decrease the stability of the well bore, which may cause irregularities in the diameter of the well bore, e.g., the diameter of some portions of the well bore may be either smaller or greater than optimally desired. In an extreme case, shale swelling may decrease the stability of the well bore to such an extent that the well bore may collapse.
A traditional method of inhibiting shale degradation during drilling has been to use an oil-based drilling fluid as opposed to an aqueous-based drilling fluid. However, environmental regulations enacted by numerous countries have limited the use of oil-based drilling fluids. Other attempts to counteract the problems associated with shale degradation during drilling have been to include shale-inhibiting components in an aqueous-based drilling fluid. As used herein, a “shale-inhibiting component” refers to a compound that demonstrates a propensity for inhibiting the tendency of shales to swell by absorbing water. Salts, such as potassium chloride, are one example of a conventional shale-inhibiting component. While salts may reduce the tendency of shales to swell, they also may flocculate the shale, resulting in undesirable fluid loss and a loss of thixotropy. Furthermore, an increase in salinity may result in a decrease in the functional characteristics of drilling fluid additives. Other examples of conventional shale-inhibiting components include, but are not limited to, amphoteric materials, polyglycols, partially hydrolyzed polyacrylamides, combinations of thickeners such as a copolymer and a polysaccharide, and polymers with a hydrophilic group and a hydrophobic group. However, these conventional shale-inhibiting components may not provide a desired level of shale swelling inhibition and/or may be environmentally undesirable in certain regions of the world.
The present invention relates to well bore stabilization and, more particularly, to treatment fluids that may reduce the tendency of shales to swell and associated methods.
In some embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophobically modified polymer that comprises a polymer backbone, the polymer backbone comprising polar heteroatoms, wherein the hydrophobically modified polymer does not comprise polyoxyethylene.
In other embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophobically modified polymer formed from a reaction of a hydrophilic polymer and a hydrophobic compound, wherein the hydrophilic polymer comprises a polyvinylamine, or a poly(vinylamine/vinyl alcohol).
In other embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophobically modified polymer formed from a reaction of a hydrophilic polymer and a hydrophobic compound, wherein the hydrophilic polymer comprises a polymer backbone and contains reactive amino groups as pendant groups or in the polymer backbone.
In other embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophobically modified polymer formed from the polymerization reaction of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, wherein the hydrophilic monomer comprises N,N-dimethylacrylamide; vinyl pyrrolidone; dimethylaminoethyl methacrylate; dimethylaminopropylmethacrylamide; vinyl amine; vinyl acetate; trimethylammoniumethyl methacrylate chloride; hydroxyethyl acrylate; vinyl sulfonic acid; vinyl phosphonic acid; vinyl caprolactam; N-vinylformamide; N,N-diallylacetamide; dimethyldiallyl ammonium halide; styrene sulfonic acid; or a quaternary salt derivative of acrylamide.
In other embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophilically modified polymer.
In yet other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophobically modified polymer that comprises a polymer backbone, the polymer backbone comprising polar heteroatoms, wherein the hydrophobically modified polymer does not comprise polyoxyethylene.
In other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophobically modified polymer formed from a reaction of a hydrophilic polymer and a hydrophobic compound, wherein the hydrophilic polymer comprises a polyvinylamine, or a poly(vinylamine/vinyl alcohol).
In other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophobically modified polymer formed from a reaction of a hydrophilic polymer and a hydrophobic compound, wherein the hydrophilic polymer comprises a polymer backbone and contains reactive amino groups as pendant groups or in the polymer backbone.
In other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophobically modified polymer formed from the polymerization reaction of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, wherein the hydrophilic monomer comprises N,N-dimethylacrylamide; vinyl pyrrolidone; dimethylaminoethyl methacrylate; dimethylaminopropylmethacrylamide; vinyl amine; vinyl acetate; trimethylammoniumethyl methacrylate chloride; hydroxyethyl acrylate; vinyl sulfonic acid; vinyl phosphonic acid; vinyl caprolactam; N-vinylformamide; N,N-diallylacetamide; dimethyldiallyl ammonium halide; styrene sulfonic acid; or a quaternary salt derivative of acrylamide.
In other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophilically modified polymer.
The features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the detailed description, which follows.
The present invention relates to well bore stabilization and, more particularly, to treatment fluids that may reduce the tendency of shales to swell and associated methods. While the methods of the present invention are useful in conjunction with a wide variety of treatment fluids (e.g., drilling fluids, completion fluids, stimulation fluids, and remedial fluids, and the like) when it is desired to stabilize the subterranean formation (e.g., by controlling the tendency of shale to swell), they are particularly useful with drilling fluids.
In some embodiments, the treatment fluids of the present invention generally comprise a base fluid and a hydrophobically modified polymer. As used herein, “hydrophobically modified” refers to the incorporation into the hydrophilic polymer structure of hydrophobic groups, wherein the alkyl chain length is from about 4 to about 22 carbons. Other additives suitable for use in treatment fluids may be added to the treatment fluids of the present invention as desired. In other embodiments, the treatment fluids of the present invention generally comprise a base fluid and a hydrophilically modified polymer. As used herein, “hydrophilically modified” refers to the incorporation into the hydrophilic polymer structure of hydrophilic groups. Among other things, the hydrophobically modified polymers and hydrophilically modified polymers of the present invention may stabilize subterranean formations containing shale, inter alia, by inhibiting the tendency of shales to swell by absorbing water.
The base fluid utilized in the treatment fluids of the present invention may be aqueous-based, or oil-based, or mixtures thereof. Where the base fluid is aqueous-based, the water utilized may be fresh water, saltwater (e.g., water containing one or more salts dissolved therein), brine (e.g., saturated saltwater), or seawater. Generally, the water may be from any source, provided that it does not contain an excess of compounds that may adversely affect other components in the drilling fluid. Where the base fluid is oil-based, examples of suitable oils include, but are not limited to, mineral oils, synthetic oils, esters, and the like. Generally, any oil that can be emulsified is suitable for use as a base fluid in the treatment fluids of the present invention. It is understood that where oil-based treatment fluids (e.g., oil-based drilling fluids) are used in the present invention, such oil-based treatment fluids may comprise an emulsified aqueous phase. The emulsification of the aqueous phase allows the water-soluble shale-inhibiting component to be incorporated into the oil-based treatment fluids without or with limited undesirable interactions between the aqueous phase and the water-soluble shale-inhibiting component.
In some embodiments, the treatment fluids of the present invention comprise a hydrophobically modified polymer. In some embodiments, the shale-inhibiting components of the present invention comprise a hydrophobically modified polymer. The hydrophobically modified polymers of the present invention typically have a molecular weight in the range of from about 100,000 to about 10,000,000. In some embodiments, the hydrophobically modified polymers are water-soluble. As used herein, “water-soluble” refers to at least 0.01 weight percent soluble in distilled water. In some embodiments, a mole ratio of a hydrophilic monomer to the hydrophobic compound in the hydrophobically modified polymer is in the range of from about 99.98:0.02 to about 90:10, wherein the hydrophilic monomer is a calculated amount present in the hydrophilic polymer. In an exemplary embodiment, the hydrophobically modified polymers may comprise a polymer backbone, the polymer backbone comprising polar heteroatoms, wherein the hydrophobically modified polymer does not comprise polyoxyethylene. Generally, the polar heteroatoms present within the polymer backbone of the hydrophobically modified polymers include, but are not limited to, oxygen, nitrogen, sulfur, or phosphorous.
In certain embodiments of the present invention, the hydrophobically modified polymers may be a reaction product of a hydrophilic polymer and a hydrophobic compound. The hydrophilic polymers suitable for forming the hydrophobically modified polymers used in the present invention should be capable of reacting with hydrophobic compounds. Suitable hydrophilic polymers include, homo-, co-, or terpolymers such as, but not limited to, polyacrylamides, polyvinylamines, poly(vinylamines/vinyl alcohols), and alkyl acrylate polymers in general. Additional examples of alkyl acrylate polymers include, but are not limited to, polydimethylaminoethyl methacrylate, polydimethylaminopropyl methacrylamide, poly(acrylamide/dimethylaminoethyl methacrylate), poly(methacrylic acid/dimethylaminoethyl methacrylate), poly(acrylamide/dimethylaminopropyl methacrylamide), poly(2-acrylamido-2-methyl propane sulfonic acid/dimethylaminoethyl methacrylate), poly (acrylic acid/dimethylaminopropyl methacrylamide), and poly(methacrylic acid/dimethylaminopropyl methacrylamide). In certain embodiments, the hydrophilic polymers contain reactive amino groups in the polymer backbone or as pendant groups, which are capable of reacting with hydrophobic compounds. In an exemplary embodiment, the hydrophilic polymers comprise dialkyl amino pendant groups. In an exemplary embodiment, the hydrophilic polymers comprise a dimethyl amino pendant group and at least one monomer comprising dimethylaminoethyl methacrylate or dimethylaminopropyl methacrylamide. In certain exemplary embodiments of the present invention, the hydrophilic polymers comprise a polymer backbone, the polymer backbone comprising polar heteroatoms, wherein the polar heteroatoms present within the polymer backbone of the hydrophilic polymers include, but are not limited to, oxygen, nitrogen, sulfur, or phosphorous. Suitable hydrophilic polymers that comprise polar heteroatoms within the polymer backbone include homo-, co-, or terpolymers, such as, but not limited to, celluloses, chitosans, polyamides, polyetheramines, polyethyleneimines, polyhydroxyetheramines, polylysines, polysulfones, gums, and starches, and derivatives thereof. In an exemplary embodiment, the starch is a cationic starch. A suitable cationic starch may be formed by reacting a starch, such as corn, maize, waxy maize, potato, and tapioca, and the like, with the reaction product of epichlorohydrin and trialkylamine.
The hydrophobic compounds that are capable of reacting with the hydrophilic polymers of the present invention include, but are not limited to, alkyl halides, sulfonates, sulfates, and organic acid derivatives. Examples of suitable organic acid derivatives include, but are not limited to, octenyl succinic acid; dodecenyl succinic acid; and anhydrides, esters, and amides of octenyl succinic acid or dodecenyl succinic acid. In certain exemplary embodiments, the hydrophobic compounds may have an alkyl chain length of from about 4 to about 22 carbons. For example, where the hydrophobic compound is an alkyl halide, the reaction between the hydrophobic compound and hydrophilic polymer may result in the quaternization of at least some of the hydrophilic polymer amino groups with an alkyl halide, wherein the alkyl chain length is from about 4 to about 22 carbons.
In other exemplary embodiments, the hydrophobically modified polymers used in the present invention may be prepared from the polymerization reaction of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer. Examples of suitable methods of their preparation are described in U.S. Pat. No. 6,476,169, the relevant disclosure of which is incorporated herein by reference.
A variety of hydrophilic monomers may be used to form the hydrophobically modified polymers useful in the present invention. Examples of suitable hydrophilic monomers include, but are not limited to homo-, co-, and terpolymers of acrylamide, 2-acrylamido-2-methyl propane sulfonic acid, N,N-dimethylacrylamide, vinyl pyrrolidone, dimethylaminoethyl methacrylate, acrylic acid, dimethylaminopropylmethacrylamide, vinyl amine, vinyl acetate, trimethylammoniumethyl methacrylate chloride, methacrylamide, hydroxyethyl acrylate, vinyl sulfonic acid, vinyl phosphonic acid, methacrylic acid, vinyl caprolactam, N-vinylformamide, N,N-diallylacetamide, dimethyldiallyl ammonium halide, itaconic acid, styrene sulfonic acid, methacrylamidoethyltrimethyl ammonium halide, quaternary salt derivatives of acrylamide, and quaternary salt derivatives of acrylic acid.
A variety of hydrophobically modified hydrophilic monomers also may be used to form the hydrophobically modified polymers useful in the present invention. Examples of suitable hydrophobically modified hydrophilic monomers include, but are not limited to, alkyl acrylates, alkyl methacrylates, alkyl acrylamides, alkyl methacrylamides alkyl dimethylammoniumethyl methacrylate halides, and alkyl dimethylammoniumpropyl methacrylamide halides, wherein the alkyl groups have from about 4 to about 22 carbon atoms. In an exemplary embodiment, the hydrophobically modified hydrophilic monomer comprises octadecyldimethylammoniumethyl methacrylate bromide, hexadecyldimethylammoniumethyl methacrylate bromide, hexadecyldimethylammoniumpropyl methacrylamide bromide, 2-ethylhexyl methacrylate, or hexadecyl methacrylamide.
The hydrophobically modified polymers formed from the above-described polymerization reaction may have estimated molecular weights in the range of from about 100,000 to about 10,000,000 and mole ratios of the hydrophilic monomer(s) to the hydrophobically modified hydrophilic monomer(s) in the range of from about 99.98:0.02 to about 90:10. Suitable hydrophobically modified polymers having molecular weights and mole ratios in the ranges set forth above include, but are not limited to, acrylamide/octadecyldimethylammoniumethyl methacrylate bromide copolymer, dimethylaminoethyl methacrylate/hexadecyldimethylammoniumethyl methacrylate bromide copolymer, dimethylaminoethyl methacrylate/vinyl pyrrolidone/hexadecyldimethylammoniumethyl methacrylate bromide terpolymer and acrylamide/2-acrylamido-2-methyl propane sulfonic acid/2-ethylhexyl methacrylate terpolymer.
In some embodiments, the hydrophobically modified polymers of the present invention may be present in the treatment fluids in an amount sufficient to provide the desired level of inhibition of shale swelling. Even further, in some embodiments, the hydrophobically modified polymers may be present in the treatment fluids of the present invention in an amount in the range of from about 0.02% to about 10% by weight of the treatment fluid. Even further, in certain exemplary embodiments, the hydrophobically modified polymers may be present in the treatment fluids of the present invention in an amount in the range of from about 0.05% to about 1% by weight of the treatment fluid.
In some embodiments, the treatment fluids of the present invention comprise a hydrophilically modified polymer. In some embodiments, the shale-inhibiting components of the present invention comprise a hydrophilically modified polymer. The hydrophilically modified polymers used in the present invention typically have a molecular weight in the range of from about 100,000 to about 10,000,000. In some embodiments, the hydrophilically modified polymers are water-soluble. In an exemplary embodiment, the hydrophilically modified polymers comprise a polymer backbone, the polymer backbone comprising polar heteroatoms. Generally, the polar heteroatoms present within the polymer backbone of the hydrophilically modified polymers include, but are not limited to, oxygen, nitrogen, sulfur, or phosphorous.
In certain embodiments of the present invention, the hydrophilically modified polymers may be a reaction product of a hydrophilic polymer and a hydrophilic compound. The hydrophilic polymers suitable for forming the hydrophilically modified polymers used in the present invention should be capable of reacting with hydrophilic compounds. In certain exemplary embodiments, suitable hydrophilic polymers include homo-, co-, or terpolymers, such as, but not limited to, polyacrylamides, polyvinylamines, poly(vinylamines/vinyl alcohols), and alkyl acrylate polymers in general. Additional examples of alkyl acrylate polymers include, but are not limited to, polydimethylaminoethyl methacrylate, polydimethylaminopropyl methacrylamide, poly(acrylamide/dimethylaminoethyl methacrylate), poly(methacrylic acid/dimethylaminoethyl methacrylate), poly(2-acrylamido-2-methyl propane sulfonic acid/dimethylaminoethyl methacrylate), poly(acrylamide/dimethylaminopropyl methacrylamide), poly (acrylic acid/dimethylaminopropyl methacrylamide), and poly(methacrylic acid/dimethylaminopropyl methacrylamide). In certain embodiments, the hydrophilic polymers contain reactive amino groups in the polymer backbone or as pendant groups, which are capable of reacting with hydrophilic compounds. In an exemplary embodiment, the hydrophilic polymers comprise dialkyl amino pendant groups. In an exemplary embodiment, the hydrophilic polymers comprise a dimethyl amino pendant group and at least one monomer comprising dimethylaminoethyl methacrylate or dimethylaminopropyl methacrylamide. In another exemplary embodiment of the present invention, the hydrophilic polymers comprise a polymer backbone, the polymer backbone comprising polar heteroatoms, wherein the polar heteroatoms present within the polymer backbone of the hydrophilic polymers include, but are not limited to, oxygen, nitrogen, sulfur, or phosphorous. Suitable hydrophilic polymers comprising polar heteroatoms within the polymer backbone include homo-, co-, or terpolymers such as, but not limited to, celluloses, chitosans, polyamides, polyetheramines, polyethyleneimines, polyhydroxyetheramines, polylysines, polysulfones, gums, and starches, and derivatives thereof. In an exemplary embodiment, the starch is a cationic starch. A suitable cationic starch may be formed by reacting a starch, such as corn, maize, waxy maize, potato, and tapioca, and the like, with the reaction product of epichlorohydrin and trialkylamine.
The hydrophilic compounds suitable for reaction with the hydrophilic polymers include, but are not limited to, polyethers comprising a halogens, sulfonates, sulfates, and organic acid derivatives. Examples of suitable polyethers include, but are not limited to, polyethylene oxides, polypropylene oxides, and polybutylene oxides, and copolymers, terpolymers, and mixtures thereof. In an exemplary embodiment, the polyether comprises an epichlorohydrin-terminated polyethylene oxide methyl ether.
The hydrophilically modified polymers formed from the reaction of a hydrophilic polymer and a hydrophilic compound may have estimated molecular weights in the range of from about 100,000 to about 10,000,000 and may have weight ratios of the hydrophilic polymers to the hydrophilic compounds in the range of from about 1:1 to about 10:1. Suitable hydrophilically modified polymers having molecular weights and weight ratios in the ranges set forth above include, but are not limited to, the reaction product of polydimethylaminoethyl methacrylate with epichlorohydrin-terminated polyethyleneoxide methyl ether; the reaction product of polydimethylaminopropyl methacrylamide with epichlorohydrin-terminated polyethyleneoxide methyl ether; and the reaction product of poly(acrylamide/dimethylaminopropyl methacrylamide) with epichlorohydrin-terminated polyethyleneoxide methyl ether. In an exemplary embodiment, the hydrophilically modified polymers comprise the reaction product of a polydimethylaminoethyl methacrylate with epichlorohydrin-terminated polyethyleneoxide methyl ether having a weight ratio of polydimethylaminoethyl methacrylate to epichlorohydrin-terminated polyethyleneoxide methyl ether of 3:1.
In some embodiments, the hydrophilically modified polymers of the present invention generally may be present in the treatment fluids in an amount sufficient to provide the desired level of inhibition of shale swelling. Even further, in some embodiments, the hydrophilically modified polymers may be present in the treatment fluids of the present invention in an amount in the range of from about 0.02% to about 10% by weight of the treatment fluid. Even further, in certain exemplary embodiments, the hydrophilically modified polymers may be present in the treatment fluids of the present invention in an amount in the range of from about 0.05% to about 1% by weight of the treatment fluid.
Additional additives may be added to the treatment fluids of the present invention as deemed appropriate by one skilled in the art for improving the performance of the treatment fluid with respect to one or more properties. Examples of such additives include, but are not limited to, emulsifiers, viscosifying agents, fluid loss control additives, salts, and weighting agents, and numerous other additives suitable for use in subterranean operations.
The treatment fluids of the present invention may be utilized for carrying out a variety of subterranean well treatments, including, but not limited to, drilling and completion operations. Treating a subterranean formation containing shales may include drilling a well bore in or near a portion of the subterranean formation. In certain exemplary embodiments, where the treatment fluids of the present invention are used with drilling operations, a drilling fluid that comprises a base fluid and a shale-inhibiting component of the present invention may be circulated into a well bore through the inside of a drill string, out through the drill bit, and up to the surface through the annulus between the drill string and the well bore. In some embodiments, the hydrophobically modified polymers and/or hydrophilically modified polymers may be added to a treatment fluid, inter alia, to reduce the tendency of shales to swell when exposed to the treatment fluid.
In some embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophobically modified polymer that comprises a polymer backbone, the polymer backbone comprising polar heteroatoms, wherein the hydrophobically modified polymer does not comprise polyoxyethylene.
In other embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophobically modified polymer formed from a reaction of a hydrophilic polymer and a hydrophobic compound, wherein the hydrophilic polymer comprises a polyvinylamine, or a poly(vinylamine/vinyl alcohol).
In other embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophobically modified polymer formed from a reaction of a hydrophilic polymer and a hydrophobic compound, wherein the hydrophilic polymer comprises a polymer backbone and contains reactive amino groups as pendant groups or in the polymer backbone.
In other embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophobically modified polymer formed from the polymerization reaction of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, wherein the hydrophilic monomer comprises N,N-dimethylacrylamide; vinyl pyrrolidone; dimethylaminoethyl methacrylate; dimethylaminopropylmethacrylamide; vinyl amine; vinyl acetate; trimethylammoniumethyl methacrylate chloride; hydroxyethyl acrylate; vinyl sulfonic acid; vinyl phosphonic acid; vinyl caprolactam; N-vinylformamide; N,N-diallylacetamide; dimethyldiallyl ammonium halide; styrene sulfonic acid; or a quaternary salt derivative of acrylamide.
In other embodiments, the present invention provides a method of stabilizing a subterranean formation that comprises a shale. The method comprises contacting the subterranean formation that comprises the shale with a treatment fluid, the treatment fluid comprising a base fluid, and a hydrophilically modified polymer.
In yet other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophobically modified polymer that comprises a polymer backbone, the polymer backbone comprising polar heteroatoms, wherein the hydrophobically modified polymer does not comprise polyoxyethylene.
In other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophobically modified polymer formed from a reaction of a hydrophilic polymer and a hydrophobic compound, wherein the hydrophilic polymer comprises a polyvinylamine, or a poly(vinylamine/vinyl alcohol).
In other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophobically modified polymer formed from a reaction of a hydrophilic polymer and a hydrophobic compound, wherein the hydrophilic polymer comprises a polymer backbone and contains reactive amino groups as pendant groups or in the polymer backbone.
In other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophobically modified polymer formed from the polymerization reaction of at least one hydrophilic monomer and at least one hydrophobically modified hydrophilic monomer, wherein the hydrophilic monomer comprises N,N-dimethylacrylamide; vinyl pyrrolidone; dimethylaminoethyl methacrylate; dimethylaminopropylmethacrylamide; vinyl amine; vinyl acetate; trimethylammoniumethyl methacrylate chloride; hydroxyethyl acrylate; vinyl sulfonic acid; vinyl phosphonic acid; vinyl caprolactam; N-vinylformamide; N,N-diallylacetamide; dimethyldiallyl ammonium halide; styrene sulfonic acid; or a quaternary salt derivative of acrylamide.
In other embodiments, the present invention provides a shale-inhibiting component that comprises a hydrophilically modified polymer.
To facilitate a better understanding of the present invention, the following examples of preferred embodiments are given. In no way should the following examples be read to limit, or define, the scope of the invention.
Shale erosion tests were performed on two different fluid samples, to determine the ability of the fluid samples to prevent shale from eroding in the presence of an aqueous medium. These tests were intended to mimic the exposure of drill cuttings to a particular drilling fluid during transport to the surface through a well bore annulus.
A sample of dried shale was ground and sieved through both a 6-mesh screen and a 14-mesh screen. U.S. Standard Sieve Series No. 6 and No. 14 screens were employed. Ground shale particles that pass through the 6-mesh screen but collected on the 14-mesh screen, e.g., particles of a size less than 6-mesh but greater than 14-mesh, were used for the shale erosion tests. For each fluid to be tested, a 40-gram sample of sized shale was weighed and selected. Next, the 40-gram sized shale sample was put into one laboratory barrel (350 ml) of each of the fluid samples. The fluid samples were then put into an oven and hot rolled at 150° F. for 16 hours. Next, the fluid samples were sieved through the 14-mesh screen and the retained solids were washed, dried, and weighed. The percent erosion was calculated based on the weight loss, corrected for the moisture content (7.67%) of the original sample. Table 1 below lists the shale erosion for each fluid tested.
Fluid Sample No. 1 comprised 100% deionized water. The shale erosion was 100%.
Fluid Sample No. 2 comprised deionized water and 1% of a hydrophilically modified polymer by weight of the deionized water. The hydrophilically modified polymer used was the reaction product of a polydimethylaminoethyl methacrylate with epichlorohydrin-terminated polyethyleneoxide methyl ether having a weight ratio of polydimethylaminoethyl methacrylate to epichlorohydrin-terminated polyethyleneoxide methyl ether of 3:1. The shale erosion was 33%.
Thus, this example indicates, inter alia, that Fluid Sample No. 2, which comprises a hydrophilically modified polymer of the present invention, provided improved shale erosion.
Therefore, the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned as well as those that are inherent therein. While numerous changes may be made by those skilled in the art, such changes are encompassed within the spirit of this invention as defined by the appended claims.
This application is a continuation-in-part of U.S. application Ser. No. 10/236,722 entitled “Compositions for and Methods of Stabilizing Subterranean Formations Containing Clays,” filed on Sep. 6, 2002, now U.S. Pat. No. 7,091,159 and U.S. application Ser. No. 10/806,894 entitled “Permeability-Modifying Drilling fluids and Methods of Use,” filed on Mar. 23, 2004.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2278838 | Groote et al. | Apr 1942 | A |
| 2670329 | Jones | Feb 1954 | A |
| 2687375 | Fischer et al. | Aug 1954 | A |
| 2689244 | Jones | Sep 1954 | A |
| 2819278 | Jen-Pu et al. | Jan 1958 | A |
| 2843573 | Melamed | Jul 1958 | A |
| 2863832 | Perrine | Dec 1958 | A |
| 2877179 | Hughes | Mar 1959 | A |
| 2910436 | Fatt et al. | Oct 1959 | A |
| 3008898 | Hughes | Nov 1961 | A |
| 3052298 | Mallot | Sep 1962 | A |
| 3065247 | De Groote et al. | Nov 1962 | A |
| 3138205 | Kerver et al. | Jun 1964 | A |
| 3215199 | Dilgren | Nov 1965 | A |
| 3251415 | Bombardieri et al. | May 1966 | A |
| 3251778 | Dickson et al. | May 1966 | A |
| 3258428 | Dickson et al. | Jun 1966 | A |
| 3265512 | Dickson et al. | Aug 1966 | A |
| 3271307 | Dickson et al. | Sep 1966 | A |
| 3297090 | Dilgren | Jan 1967 | A |
| 3307630 | Dilgren et al. | Mar 1967 | A |
| 3326890 | Engelskirchen et al. | Jun 1967 | A |
| 3336980 | Rike | Aug 1967 | A |
| 3347789 | Dickson et al. | Oct 1967 | A |
| 3382924 | Valey et al. | May 1968 | A |
| 3404114 | Walter et al. | Oct 1968 | A |
| 3434971 | Atkins | Mar 1969 | A |
| 3441085 | Gidley | Apr 1969 | A |
| 3451818 | Wareham | Jun 1969 | A |
| 3489222 | Millhoune et al. | Jan 1970 | A |
| 3601194 | Gallus | Aug 1971 | A |
| 3615794 | Nimerick | Oct 1971 | A |
| 3637656 | Germino et al. | Jan 1972 | A |
| 3647507 | Ashcraft | Mar 1972 | A |
| 3647567 | Schweri et al. | Mar 1972 | A |
| 3689418 | Cenci et al. | Sep 1972 | A |
| 3689468 | Cenci et al. | Sep 1972 | A |
| 3708013 | Dismukes | Jan 1973 | A |
| 3709298 | Pramann | Jan 1973 | A |
| 3744566 | Szabo et al. | Jul 1973 | A |
| 3818991 | Nimerick | Jun 1974 | A |
| 3902557 | Shaughnessy et al. | Sep 1975 | A |
| 3910862 | Barabas et al. | Oct 1975 | A |
| 3943060 | Martin et al. | Mar 1976 | A |
| 3983941 | Fitch | Oct 1976 | A |
| 4029544 | Jarowenko et al. | Jun 1977 | A |
| 4052343 | Cunningham | Oct 1977 | A |
| 4052345 | Austin et al. | Oct 1977 | A |
| 4129183 | Kalfoglou | Dec 1978 | A |
| 4129534 | Cunningham | Dec 1978 | A |
| 4142595 | Anderson et al. | Mar 1979 | A |
| 4152274 | Phillips et al. | May 1979 | A |
| 4158521 | Anderson et al. | Jun 1979 | A |
| 4158726 | Kamada et al. | Jun 1979 | A |
| 4228277 | Landoll | Oct 1980 | A |
| 4299710 | Dupre et al. | Nov 1981 | A |
| 4306981 | Blair, Jr. | Dec 1981 | A |
| 4337828 | Blair, Jr. | Jul 1982 | A |
| 4366071 | McLaughlin et al. | Dec 1982 | A |
| 4366072 | McLaughlin et al. | Dec 1982 | A |
| 4366073 | McLaughlin et al. | Dec 1982 | A |
| 4366074 | McLaughlin et al. | Dec 1982 | A |
| 4374739 | McLaughlin et al. | Feb 1983 | A |
| 4393939 | Smith et al. | Jul 1983 | A |
| 4395340 | McLaughlin | Jul 1983 | A |
| 4401789 | Gideon | Aug 1983 | A |
| 4409110 | Borchardt et al. | Oct 1983 | A |
| 4439334 | Borchardt | Mar 1984 | A |
| 4440649 | Loftin et al. | Apr 1984 | A |
| 4441556 | Powers et al. | Apr 1984 | A |
| 4447342 | Borchardt et al. | May 1984 | A |
| 4460627 | Weaver et al. | Jul 1984 | A |
| 4462718 | McLaughlin et al. | Jul 1984 | A |
| 4499214 | Sortwell | Feb 1985 | A |
| 4532052 | Weaver et al. | Jul 1985 | A |
| 4536297 | Loftin et al. | Aug 1985 | A |
| 4536303 | Borchardt | Aug 1985 | A |
| 4536305 | Borchardt et al. | Aug 1985 | A |
| 4552670 | Lipowski et al. | Nov 1985 | A |
| 4554081 | Borchardt et al. | Nov 1985 | A |
| 4563292 | Borchardt | Jan 1986 | A |
| 4604216 | Irvin et al. | Aug 1986 | A |
| 4608139 | Craun et al. | Aug 1986 | A |
| 4619776 | Mondshine | Oct 1986 | A |
| 4627926 | Peiffer et al. | Dec 1986 | A |
| 4631138 | Johns et al. | Dec 1986 | A |
| 4662448 | Ashford et al. | May 1987 | A |
| 4671883 | Connell | Jun 1987 | A |
| 4693639 | Hollenbeak et al. | Sep 1987 | A |
| 4699722 | Dymond et al. | Oct 1987 | A |
| 4702319 | Bock et al. | Oct 1987 | A |
| 4730028 | Bock et al. | Mar 1988 | A |
| 4814096 | Evani | Mar 1989 | A |
| 4828725 | Lai et al. | May 1989 | A |
| 4828726 | Himes et al. | May 1989 | A |
| 4856590 | Caillier | Aug 1989 | A |
| 4870167 | Zody et al. | Sep 1989 | A |
| 4941537 | Langemeier et al. | Jul 1990 | A |
| 4956104 | Cowan et al. | Sep 1990 | A |
| 4959432 | Fan et al. | Sep 1990 | A |
| 4960876 | Molteni et al. | Oct 1990 | A |
| 4993448 | Karydas et al. | Feb 1991 | A |
| 5051197 | Kalfayan et al. | Sep 1991 | A |
| 5071934 | Peiffer | Dec 1991 | A |
| 5097904 | Himes | Mar 1992 | A |
| 5105886 | Strubhar et al. | Apr 1992 | A |
| 5146986 | Dalrymple | Sep 1992 | A |
| 5160642 | Schield et al. | Nov 1992 | A |
| 5197544 | Himes | Mar 1993 | A |
| 5208216 | Williamson et al. | May 1993 | A |
| 5244042 | Dovan et al. | Sep 1993 | A |
| 5248665 | Hale et al. | Sep 1993 | A |
| 5256651 | Phelps et al. | Oct 1993 | A |
| 5271466 | Harms | Dec 1993 | A |
| 5342530 | Aften et al. | Aug 1994 | A |
| 5379841 | Pusch et al. | Jan 1995 | A |
| 5382371 | Stahl et al. | Jan 1995 | A |
| 5407909 | Goodhue et al. | Apr 1995 | A |
| 5424284 | Patel et al. | Jun 1995 | A |
| 5445223 | Nelson et al. | Aug 1995 | A |
| 5473059 | Yeh | Dec 1995 | A |
| 5482116 | El-Rabaa et al. | Jan 1996 | A |
| 5566760 | Harris | Oct 1996 | A |
| 5597783 | Audibert et al. | Jan 1997 | A |
| 5607902 | Smith et al. | Mar 1997 | A |
| 5637556 | Argillier et al. | Jun 1997 | A |
| 5643460 | Marble et al. | Jul 1997 | A |
| 5646093 | Dino | Jul 1997 | A |
| 5663123 | Goodhue et al. | Sep 1997 | A |
| 5669456 | Audibert et al. | Sep 1997 | A |
| 5681796 | Nimerick | Oct 1997 | A |
| 5704426 | Rytlewski et al. | Jan 1998 | A |
| 5720347 | Audibert et al. | Feb 1998 | A |
| 5728653 | Audibert et al. | Mar 1998 | A |
| 5735349 | Dawson et al. | Apr 1998 | A |
| 5887653 | Bishop et al. | Mar 1999 | A |
| 5908814 | Patel et al. | Jun 1999 | A |
| 5944106 | Dalrymple et al. | Aug 1999 | A |
| 5972848 | Audibert et al. | Oct 1999 | A |
| 5979557 | Card et al. | Nov 1999 | A |
| 5990052 | Harris | Nov 1999 | A |
| 6020289 | Dymond | Feb 2000 | A |
| 6047773 | Zeltmann et al. | Apr 2000 | A |
| 6070664 | Dalrymple et al. | Jun 2000 | A |
| 6124245 | Patel | Sep 2000 | A |
| 6162766 | Muir et al. | Dec 2000 | A |
| 6187839 | Eoff et al. | Feb 2001 | B1 |
| 6194356 | Jones et al. | Feb 2001 | B1 |
| 6209646 | Reddy et al. | Apr 2001 | B1 |
| 6228812 | Dawson et al. | May 2001 | B1 |
| 6237687 | Barbee, Jr. et al. | May 2001 | B1 |
| 6242390 | Mitchell et al. | Jun 2001 | B1 |
| 6248697 | Goodhue, Jr. et al. | Jun 2001 | B1 |
| 6253851 | Schroeder, Jr. et al. | Jul 2001 | B1 |
| 6277900 | Oswald et al. | Aug 2001 | B1 |
| 6281172 | Warren et al. | Aug 2001 | B1 |
| 6283210 | Soliman et al. | Sep 2001 | B1 |
| 6291404 | House | Sep 2001 | B2 |
| 6358889 | Waggenspack et al. | Mar 2002 | B2 |
| 6359047 | Thieu et al. | Mar 2002 | B1 |
| 6364016 | Dalrymple et al. | Apr 2002 | B1 |
| 6380137 | Heier et al. | Apr 2002 | B1 |
| 6454003 | Chang et al. | Sep 2002 | B1 |
| 6476169 | Eoff et al. | Nov 2002 | B1 |
| 6476283 | Devore et al. | Nov 2002 | B1 |
| 6497283 | Eoff et al. | Dec 2002 | B1 |
| 6516885 | Munday | Feb 2003 | B1 |
| 6520255 | Tolman et al. | Feb 2003 | B2 |
| 6562762 | Cowan et al. | May 2003 | B2 |
| 6569983 | Treybig et al. | May 2003 | B1 |
| 6601648 | Ebinger | Aug 2003 | B2 |
| 6607035 | Reddy et al. | Aug 2003 | B1 |
| 6609578 | Patel et al. | Aug 2003 | B2 |
| 6626241 | Nguyen | Sep 2003 | B2 |
| 6627719 | Whipple et al. | Sep 2003 | B2 |
| 6637517 | Samuel et al. | Oct 2003 | B2 |
| 6656885 | House et al. | Dec 2003 | B2 |
| 6662874 | Surjaatmadja et al. | Dec 2003 | B2 |
| 6702044 | Reddy et al. | Mar 2004 | B2 |
| 6710107 | Audibert et al. | Mar 2004 | B2 |
| 6723683 | Crossman et al. | Apr 2004 | B2 |
| 6743288 | Eoff et al. | Jun 2004 | B2 |
| 6756345 | Pakulski et al. | Jun 2004 | B2 |
| 6764981 | Eoff et al. | Jul 2004 | B1 |
| 6767867 | Chatterji et al. | Jul 2004 | B2 |
| 6767869 | DiLullo et al. | Jul 2004 | B2 |
| 6780822 | Cowan et al. | Aug 2004 | B2 |
| 6787506 | Blair et al. | Sep 2004 | B2 |
| 6790812 | Halliday et al. | Sep 2004 | B2 |
| 6800593 | Dobson, Jr. et al. | Oct 2004 | B2 |
| 6803348 | Jones et al. | Oct 2004 | B2 |
| 6846420 | Reddy et al. | Jan 2005 | B2 |
| 6855672 | Poelker et al. | Feb 2005 | B2 |
| 6884760 | Brand et al. | Apr 2005 | B1 |
| 6913081 | Powell et al. | Jul 2005 | B2 |
| 6933381 | Mallon et al. | Aug 2005 | B2 |
| 6962203 | Funchess | Nov 2005 | B2 |
| 6978836 | Nguyen et al. | Dec 2005 | B2 |
| 6981552 | Reddy et al. | Jan 2006 | B2 |
| 7007752 | Reddy et al. | Mar 2006 | B2 |
| 7008908 | Chan et al. | Mar 2006 | B2 |
| 7036587 | Munoz, Jr. et al. | May 2006 | B2 |
| 7036589 | Nguyen | May 2006 | B2 |
| 7081439 | Sullivan et al. | Jul 2006 | B2 |
| 7087554 | Youngson et al. | Aug 2006 | B2 |
| 7091159 | Eoff et al. | Aug 2006 | B2 |
| 7114568 | Eoff et al. | Oct 2006 | B2 |
| 7117942 | Dalrymple et al. | Oct 2006 | B2 |
| 7159656 | Eoff et al. | Jan 2007 | B2 |
| 7178610 | Bell | Feb 2007 | B2 |
| 7182136 | Dalrymple et al. | Feb 2007 | B2 |
| 7207387 | Eoff et al. | Apr 2007 | B2 |
| 7216707 | Eoff et al. | May 2007 | B2 |
| 7220708 | Zamora et al. | May 2007 | B2 |
| 7398825 | Nguyen et al. | Jul 2008 | B2 |
| 7427583 | Couillet et al. | Sep 2008 | B2 |
| 20020123433 | Goodhue, Jr. et al. | Sep 2002 | A1 |
| 20030013871 | Mallon et al. | Jan 2003 | A1 |
| 20030019627 | Qu et al. | Jan 2003 | A1 |
| 20030104948 | Poelker et al. | Jun 2003 | A1 |
| 20030191030 | Blair et al. | Oct 2003 | A1 |
| 20040102331 | Chan et al. | May 2004 | A1 |
| 20040171495 | Zamora et al. | Sep 2004 | A1 |
| 20040229756 | Eoff et al. | Nov 2004 | A1 |
| 20040229758 | Eoff et al. | Nov 2004 | A1 |
| 20050000694 | Dalrymple et al. | Jan 2005 | A1 |
| 20050155796 | Eoff et al. | Jul 2005 | A1 |
| 20050164894 | Eoff et al. | Jul 2005 | A1 |
| 20050178549 | Eoff et al. | Aug 2005 | A1 |
| 20050199396 | Sierra et al. | Sep 2005 | A1 |
| 20050230114 | Eoff et al. | Oct 2005 | A1 |
| 20050230116 | Eoff et al. | Oct 2005 | A1 |
| 20050279502 | Eoff et al. | Dec 2005 | A1 |
| 20050284632 | Dalrymple et al. | Dec 2005 | A1 |
| 20070012445 | Nguyen et al. | Jan 2007 | A1 |
| 20080070805 | Munoz et al. | Mar 2008 | A1 |
| 20080070807 | Munoz et al. | Mar 2008 | A1 |
| 20080070808 | Munoz et al. | Mar 2008 | A1 |
| 20080139411 | Harris et al. | Jun 2008 | A1 |
| 20080173448 | Nguyen et al. | Jul 2008 | A1 |
| 20080196897 | Nguyen | Aug 2008 | A1 |
| Number | Date | Country |
|---|---|---|
| 0 383 337 | Aug 1990 | EP |
| 0 896 122 | Feb 1999 | EP |
| 1 193 365 | Apr 2002 | EP |
| 1 312 753 | May 2003 | EP |
| 2221940 | Feb 1990 | GB |
| 2335428 | Sep 1999 | GB |
| WO 9949183 | Sep 1999 | WO |
| WO 9950530 | Oct 1999 | WO |
| WO 0078890 | Dec 2000 | WO |
| WO 02097236 | Dec 2002 | WO |
| WO 03056130 | Jul 2003 | WO |
| WO 2004022667 | Mar 2004 | WO |
| WO 2004022667 | Mar 2004 | WO |
| WO 2004094781 | Nov 2004 | WO |
| WO 2004101706 | Nov 2004 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20040220058 A1 | Nov 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10236722 | Sep 2002 | US |
| Child | 10862132 | US | |
| Parent | 10806894 | Mar 2004 | US |
| Child | 10236722 | US |
