Abstract: The present invention relates to a method for preparing microgels of controlled size. According to the method, a gelling composition comprising a polymer and a crosslinking additive intended for the polymer is injected into a porous and permeable medium, and a monodisperse solution of microgels of substantially constant size is recovered at the outlet. The invention also relates to an application of the method for reducing the permeability of porous and permeable formations of reservoir rock type.

Abstract: A plugging fluid for plugging a subterranean formation zone surrounding a drill hole comprises an emulsion comprising a dispersed aqueous phase containing an aqueous base and a continuous hydrophobic phase containing a polymer consisting of a grafted cellulose ether derivative, a surfactant and a crosslinking activator of the polymer. The polymer is preferably 2-hydroxyethyl cellulose grafted with vinyl phosphonic acid. Upon shearing, preferably through the drilling bit, the emulsion inverts so that the rupture of the emulsion droplets releases the crosslinking activator into the water phase thus forming a gel structure.

Abstract: A water shut-off is provided in a hydrocarbon well by injecting a first chemical composition, effective as a relative permeability modifier polymer, into the hydrocarbon and a water zone of the well followed immediately by the injection of a second chemical composition, which forms a flow blocking polymer composition, into the zones and, after a shut-in period for reaction of the relative permeability modifier polymer, back producing the polymer compositions from they hydrocarbon zones to provide a path for the hydrocarbons from the zones while allowing the flow blocking polymer compositions to form the water shut-off in the water zones.

Abstract: The invention is a novel drilling fluid additive comprising particles of elastomer which are capable of swelling upon contact with a hydrocarbon fluid. The swelling of the elastomer is gradual, allowing the elastomer to reach the lost circulation zone before significant swelling occurs. Once in the lost circulation zone, the polymer expands sealing off the lost circulation zone. A method for preventing drilling fluid loss is also provided.

Abstract: Subterranean formation treating fluid concentrates, treating fluids and methods are provided by the present invention. The treating fluid concentrates are basically comprised of water and a substantially fully hydrated depolymerized polymer. The treating fluids which are formed by adding water to the treating fluid concentrates are basically comprised of water, a substantially fully hydrated depolymerized polymer and a crosslinking agent for crosslinking the hydrated depolymerized polymer.

Abstract: Herein is described a method of consolidating a subterranean formation or repairing a gravel pack, comprising (i) providing a consolidating fluid, wherein the consolidating fluid comprises a gel component and a gel-forming agent; and (ii) injecting the consolidating fluid into the formation or gravel pack, under conditions wherein the gel component forms a flexible gel, thereby consolidating the formation.

Abstract: The present invention relates to a method of breaking an aqueous fracturing fluid comprising introducing said aqueous fracturing fluid into contact with an encapsulated viscosity reducing agent said encapsulated viscosity reducing agent comprising an aqueous fluid soluble breaker for said fracturing fluid encapsulated within a membrane comprising a partially hydrolyzed acrylic crosslinked with either an aziridine prepolymer or a carbodiimide, said membrane having an embrittlement effective amount of a micron sized particulate present therein and said membrane having been cured at a temperature of at least about 115° F., such that an aqueous fluid in said fracturing fluid can contact said breaker after fracture failure of said membrane to dissolve at least a portion of said breaker and break the fracturing fluid in contact therewith.

Abstract: A chemical system and method to stop or minimize fluid loss during completion of wells penetrating hydrocarbon formations are provided. The inventions relates to formulating a highly stable crosslinked hydroxyethyl cellulose (HEC), control released viscosity reduction additives, and user friendly packaging. The chemical system contains a linear HEC polymer solution, a low solubility compound which slowly raises the fluid pH, a chelating agent which further increases the pH level beyond the equilibrium achievable by the low solubility compound, a metal crosslinker which crosslinks HEC at elevated pH, a crosslink delaying agent which allows fluid viscosity to remain low until the fluid reaches the subterranean formation, and optionally an internal breaker. The chemical additives are packaged as an integrated pallet and transported to a field location which allows operators to conveniently mix them before pumping.

Abstract: Improved hardenable resin compositions and methods of consolidating particulate solids in subterranean zones penetrated by well bores are provided. The improved hardenable resin compositions of the invention are basically comprised of a hardenable organic resin, an aminosilane resin-to-particulate solid coupling agent, a viscous carrier fluid breaker for breaking separating films of viscous carrier fluid between resin coated particulate solids and a surface active agent for causing the resin composition to flow to the contact points between resin coated particulate solids.

Abstract: The present invention provides improved cross-linked well treating fluids and methods for preparing and using the fluids in treating wells such as fracturing subterranean zones therein. The improved cross-linked treating fluids comprise water, a galactomannan gelling agent, a cross-linking agent for cross-linking the galactomannan gelling agent, and a viscosity stabilizing agent selected from the group consisting of formaldehyde, formic acid, or mixtures thereof. The viscosity stabilizing agent alters the properties of the well treating fluids and enables them to retain their viscosity over prolonged periods of time when compared to prior well treating fluids.

Abstract: The invention is the method of treating of a well, a formation, or both, with the solids, liquids, or apparatuses, by 1) encasing the solids, liquids, or apparatuses in a water-soluble shell, 2) conveying the encased solids, liquids, or gases to the predetermined location in the well, and then 3) allowing the water-soluble shell to dissolve in the aqueous phase in the wellbore. The shell is preferably made of water-soluble polymers such as collagen, a crosslinking agent such as zolidine, optionally a hydrophobic compound such as a processed oil, and water used in processing. Other modifying or conditioning compounds, for example glycerin and other polymeric additives, may be incorporated to extend the strength or temperature range of the shell. The shell encases a variety of solids, liquids, or combinations thereof, where the solids or liquids are useful in the treatment of the well or of the producing formation.

Abstract: A CO2-foamable gelling composition and use of said composition for conformance control operations are described The gelling fluid comprises a decomposing agent to counteract the detrimental effect of CO2 on the gelling process.

Abstract: A composition for delaying the cross-linking of water soluble polymer solutions includes a boron source suspended by an organophilic clay in a solution of a non-aqueous solvent. One process of manufacturing the composition includes the steps of first suspending the organophilic clay in the non-aqueous solvent and then suspending the boron source in the organophilic clay-non-aqueous solvent suspension. Another process of manufacturing composition includes the steps of first mixing the boron source and the organophilic clay to form a dry mixture and then suspending the dry mixture of the boron source and the organophilic clay in a non-aqueous solvent. In a method of hydraulically fracturing a formation, a water soluble polymer solution with a pH between about 8.5 and 12.5 and the boron source suspended by the organophilic clay in the solution of the non-aqueous solvent are pumped into the formation under sufficient pressure to cause a fracture in the formation rock.

Abstract: A fluid that is useful in stimulation operations, and in particular, in hydraulic fracturing treatments, comprises a carrier fluid; a solvatable, crosslinkable polymer; a cross-linking agent that does not cause substantial cross-linking of the polymer at temperatures less than about 105° F. and a pH of about 10 or greater; and an organic amine stabilizing agent that has a first pKa or a pH in water of at least about 9.5. One group of such amines has the formula H2N—(R1NH)n—H where R1 is C1-C4 alkyl and n is from 1-6. In one embodiment, the cross-linking agent is an organic zirconate, such as bis(hydroxyethyl)glycine zirconate. The organic zirconate is effective to cross-link the polymer when the composition is at a temperature of at least about 105° F., and a pH of about 10 or higher, preferably a pH in the range of about 10.5-12.

Abstract: A composition for delaying the cross-linking of water soluble polymer solutions includes a boron source suspended by an organophilic clay in a solution of a non-aqueous solvent. One process of manufacturing the composition includes the steps of first suspending the organophilic clay in the non-aqueous solvent and then suspending the boron source in the organophilic clay- non-aqueous solvent suspension. Another process of manufacturing composition includes the steps of first mixing the boron source and the organophilic clay to form a dry mixture and then suspending the dry mixture of the boron source and the organophilic clay in a non-aqueous solvent. In a method of hydraulically fracturing a formation, a water soluble polymer solution with a pH between about 8.5 and 12.5 and the boron source suspended by the organophilic clay in the solution of the non-aqueous solvent are pumped into the formation under sufficient pressure to cause a fracture in the formation rock.

Abstract: Improved high temperature, low residue viscous well treating fluids and methods of using the fluids are provided by the present invention. The improved viscous well treating fluids are basically comprised of water; a hydrated galactomannan gelling agent; a retarded cross-linking composition for buffering the treating fluid and cross-linking the hydrated galactomannan gelling agent comprised of a liquid solvent, an organotitanate chelate and a borate ion producing compound; and a delayed gel breaker.

Abstract: The present invention relates to methods of treating subterranean formations with viscosified aqueous well treating compositions which break into thin fluids at static temperatures in the range of from about 150° F. to about 200° F. A breaker system is included in the compositions comprised of an alkali metal or ammonium persulfate breaker and a breaker activity delaying agent comprised of an alkali metal chlorite or hypochlorite.

Abstract: Methods and compositions for reducing the permeabilities of subterranean zones are provided. The methods of the invention are basically comprised of introducing an aqueous composition comprised of a chelated organic gelling agent and a copolymer of an ethylenically unsaturated polar monomer and an ethylenically unsaturated ester or a terpolymer or tetrapolymer of an ethylenically unsaturated polar monomer, an ethylenically unsaturated ester and a monomer selected from AMPS® and/or N-vinylpyrrolidone into the zone and then allowing the aqueous composition to form a cross-linked gel in the zone.

Abstract: A wellbore service fluid comprising viscoelastic surfactants in combination with cross-linkable, preferably hydrophobically modified, water soluble polymers is described, particularly applicable to water control operations.

Abstract: A process is provided for reducing the permeability of or fluid mobility within a carbonate-containing treatment region in or proximate to a hydrocarbon-bearing formation below an earthen surface penetrated by a well bore. The process is initiated by preparing a gelation solution at the earthen surface which includes an acrylamide polymer, a crosslinking agent, a stabilizing agent and an aqueous solvent. The stabilizing agent is an acid additive, acidic pH buffer system, or delayed acid generator. The crosslinking agent is a chromium(III) complex having one or more chromium(III) cations and one or more carboxylate anions. The gelation solution is injected into the well bore and displaced into the treatment region where it is gelled in situ to form a gel which substantially reduces the permeability of or fluid mobility within the treatment region.

Abstract: A method for reducing the permeability of a region of an underground formation by injecting a gelant solution that forms a stable gel into the region is disclosed. The gelant solution includes an aqueous solvent, about 2% to about 16% by weight of a lignosulfonate-acrylic acid graft copolymer and a sufficient concentration of a crosslinking agent to crosslink the copolymer. The lignosulfonate-acrylic acid copolymer used in the invention has an acrylic acid content of about 10% to about 50% by weight and the crosslinking agent is a complex of one or more positively charged chromium (III) species and one or more negatively charged carboxylate species. Preferably, the chromium (III) species used in the invention has a concentration of about 0.1% to about 8.0% by weight. In one preferred embodiment, the carboxylate species of the crosslinker may be selected from formate, acetate, propionate, lactate, oxalate and malonate.

Abstract: A subterranean formation is treated by introducing a fracturing treatment composition comprising a polymer treatment fluid containing a dispersion of hydrophilic water swellable particles into the formation. The water swellable particles comprise synthetic polymers that are crosslinked so that they are water insoluble, but capable of swelling in the presence of relatively small amounts of water. When used with treatment fluids containing at least a small amount of water, the particles swell and reduce fluid loss to the formation during the treatment. When used during a hydraulic fracturing treatment of a hydrocarbon bearing formation, the particles may also reduce or eliminate water production following the fracturing treatment by restricting the extension of a fracture into water-bearing formations, and/or by restricting the flow of fluids from water-bearing areas.

Abstract: A gel-breaking/gel-inhibiting composition containing at least one carboxylic acid or salt thereof is dispersed in a hydrophobic carrier fluid to break down a cross-linked polymer gel or inhibit the gelation of a polymer gel used in plugging in permeable subterranean formations containing oil-bearing zones and water-bearing zones. The composition may be used to selectively restore permeability to oil-bearing zones in formations containing a cross-linked polymer gel or to inhibit gelation in an oil-bearing zone by injection into the oil-bearing zone prior to or after treatment of the formation containing the oil-bearing zone with an aqueous polymer solution.

Abstract: For conformance treatment to plug an opening in subterranean hydrocarbon bearing formation, a conformance additive including a dry mixture of water soluble crosslinkable polymer, a crosslinking agent, and a reinforcing material of fibers and/or comminuted plant materials. The method of forming a conformance fluid includes contacting the additive with water or an aqueous solution, with a method of conforming the formation further including the step of injecting the fluid into the formation to plug the opening.

Abstract: A foamed gel composition useful in a subterranean hydrocarbon-bearing formation to reduce the permeability of a treatment region therein or control the mobility of a drive fluid in the formation. The foamed gel is formed from a crosslinkable carboxylate-containing polymer, a crosslinking agent containing a reactive transition metal cation, a polyvinyl alcohol, an aqueous solvent, and an added gas.

Abstract: For well plug treatment to plug an abandoned well, a well plug additive including a dry mixture of water soluble crosslinkable polymer, a crosslinking agent, and a reinforcing material of fibers and/or comminuted plant materials. The method of forming a well plug fluid includes contacting the additive with water or an aqueous solution, with a method of plugging the well further including the step of injecting the fluid into the wellbore.

Abstract: A process is provided for reducing the permeability of or fluid mobility within a high-temperature treatment region in or proximate to a hydrocarbon-bearing formation below an earthen surface penetrated by a well bore. The process is initiated by preparing a gelation solution at the earthen surface which includes a base loading of a high molecular weight acrylamide polymer, an additive loading of a low molecular weight acrylamide polymer, a crosslinking agent, and an aqueous solvent. The crosslinking agent is preferably a chromium(III) complex having one or more chromium(III) cations and one or more carboxylate anions. The resulting gelation solution is injected into the well bore and displaced into the treatment region where it is gelled in situ to form a gel which substantially reduces the permeability of or fluid mobility within the treatment region.

Abstract: The present invention provides improved methods of treating subterranean formations using borate cross-linking compositions and borate cross-linked well treating fluids. The borate cross-linking compositions are basically comprised of a low viscosity hydrocarbon liquid, an organophillic clay, a slightly water soluble borate, a buffer and a dispersing agent.

Abstract: For lost circulation treatment, a lost circulation additive including a dry mixture of water soluble crosslinkable polymer, a crosslinking agent, and a reinforcing material of fibers and/or comminuted plant materials. The method of forming a lost circulation fluid includes contacting the additive with water or an aqueous solution, with a method of conforming the formation further including the step of injecting the fluid into the wellbore.

Abstract: For hydraulic fracturing treatment to increase productivity of subterranean hydrocarbon bearing formation, a hydraulic fracturing additive including a dry mixture of water soluble crosslinkable polymer, a crosslinking agent, and a reinforcing material of fibers and/or comminuted plant materials. The method of forming a hydraulic fracturing fluid includes contacting the additive with water or an aqueous solution, with a method of hydraulically fracturing the formation further including the step of injecting the fluid into the wellbore.

Abstract: For well kill treatment to prevent the intrusion of formation fluids into the wellbore while the well is open, a well kill additive including a dry mixture of water soluble crosslinkable polymer, a crosslinking agent, and a reinforcing material of fibers and/or comminuted plant materials. The method of forming a well kill fluid includes contacting the additive with water or an aqueous solution, with a method of conforming the formation further including the step of injecting the fluid into the wellbore.

Abstract: The present invention provides improved foamed hardenable epoxy resin sealing compositions and methods which are particularly useful in the construction and repair of wells. The foamed epoxy resin compositions are corrosion resistant and have improved mechanical properties including elasticity and ductility.

Abstract: Methods and compositions for preventing high density well completion fluid loss are provided. The methods basically comprise the steps of preparing a high density cross-linked aqueous gelled composition having the rigidity required to resist entry into a permeable subterranean formation penetrated by a well bore, placing the high density cross-linked aqueous gelled composition in the portion of the well bore within the permeable subterranean formation and placing a high density completion fluid in the well bore behind the high density cross-linked gelled composition.

Abstract: Cationic polymer-containing gels are stable at elevated temperatures in soft and hard waters.

Abstract: A plugging liquid for plugging of a zone of a subterranean formation around a drill hole, consisting of an emulsion comprising (a) a continuous phase containing a hydrophobic liquid, an emulsifier and a crosslinking agent for a polysaccharide, and (b) a discontinuous phase containing water and a polysaccharide. A variant of the plugging composition contains in addition a weighting material in the discontinuous phase. Also described is a method for preparing the plugging liquid and a method for plugging a zone of a subterranean formation penetrated by a drill hole in fluid communication with the zone, according to which method the new plugging liquid is injected into the zone via the drill hole and is subjected to high shear forces in the drill hole, whereby the polysaccharide and the crosslinking agent are brought into contact with one another with resulting initiation of a crosslinking of the polysaccharide and the crosslinking agent and a setting of the plugging liquid.

Abstract: A composition and a process for treating a subterranean formation are disclosed. The process comprises injecting into the subterranean formation a composition which comprises a polymer, a crosslinking agent, a liquid, optionally a clay, and further optionally a weighting agent wherein the polymer forms a gel in the formation, in the presence of the crosslinking agent.

Abstract: A process employing a foamed gel in a subterranean hydrocarbon-bearing formation to reduce the permeability of a treatment region therein or control the mobility of a drive fluid in the formation. The foamed gel is formed from a crosslinkable carboxylate-containing polymer, a crosslinking agent containing a reactive transition metal cation, a polyvinyl alcohol, an aqueous solvent, and an added gas.

Abstract: A process and composition are provided for permeability reduction in a hydrocarbon-bearing formation to improve hydrocarbon recovery therefrom. The process includes placement of a crosslinked polymer gel in the treatment region preceded by surface preparation of a gelation solution which is the gel precursor. The gelation solution contains a crosslinkable polymer, a chromium(III)/carboxylate complex crosslinking agent, an inorganic fluoride salt stabilizing agent and an aqueous solvent containing hard salts. The gel is placed in the treatment region by injecting the gelation solution into a well bore in fluid communication with the formation, displacing the gelation solution into the desired treatment region and gelling the solution to completion forming the permeability-reducing gel in situ. The inorganic fluoride salt stabilizing agent promotes the long-term stability of the gel in the treatment region, particularly at high temperatures.

Abstract: A crosslinked water-based gel, for example a gel plug in an underground rock formation or a pipeline, is broken by an enzyme and a substrate which is capable of being converted by the enzyme into an organic acid which breaks down the gel. The enzyme is allowed to catalyze the conversion of the substrate into the acid to cause the breakdown of the gel.

Abstract: A method of formulating a zirconium lactate compound is accomplished by combining in solution lactic acid or a lactate salt with zirconium carbonate. The reacting solution forms zirconium lactate and carbon dioxide which is evolved as a gas from the solution. This eliminates the need to filter or wash the zirconium lactate in order to remove undesirable by-products. The zirconium lactate can be used as a crosslinking agent for crosslinking aqueous polymer gels used in such things as fracturing fluids for fracturing subterranean formations of oil and gas wells.

Abstract: A process for altering the permeability of a subterranean formation comprises injecting into the subterranean formation a gelling composition which comprises a carboxylate-containing polymer, a crosslinking agent, and a liquid such as a produced brine wherein the polymer forms a gel in the formation, in the presence of the crosslinking agent. The polymer can have a molecular weight of from about 10,000 to about 30,000,000, contain about 0.01 to about 10 mole % of a carboxylate group, and be present in the gelling composition in the range of from about 100 to about 100,000 mg per liter of the composition.

Abstract: A foam is provided having utility for improving sweep efficiency in subterranean oil-bearing formations and having specific utility for conformance improvement treatments and mobility control in such formations. The foam is a gel medium having a gas dispersed therein. The gel medium is made up of a crosslinkable polymer, a crosslinking agent, a surfactant and a liquid solvent.

Abstract: Cationic polymer-containing gels are stable at elevated temperatures in soft and hard waters.

Abstract: A composition comprising a water-in-oil polymer emulsion wherein the polymer is the reaction product of the following:(a) an ethylenically unsaturated carboxylate having between about 3 and about 6 carbon atoms;(b) an ethylenically unsaturated monomer which is nonionic in nature;(c) an ethylenically unsaturated monomer containing one or more sulfonate or sulfoalkyl groups;(d) an ethylenically unsaturated monomer having surface active properties; and(e) a crosslinking agent is provided. The composition has a multiple number of uses, such as in ink, pigment or dye thickening.

Abstract: The present invention relates to methods and compositions for reducing the production of water from water and oil producing subterranean formations. The methods basically comprise the introduction of an aqueous polymer composition into the water producing zones of the formation which cross-links after being placed therein. The compositions of the invention are comprised of a heavy brine and a graft copolymer of a hydrophilic polymer and a phosphonate.

Abstract: The present invention provides a method of controlling fluid loss to a permeable formation penetrated by a wellbore. A novel fluid loss agent is prepared by forming a crosslinked polymer gel which then is sheared to break the gel into discrete particles of a particular size range. A slurry then is formed of the particles by dispersing the particles in an aqueous fluid having a density similar to that of the gel particles. The slurry then is introduced into contact with the permeable formation and a filter cake of the particles is formed upon contact with the formation and loss of the slurrying fluid to the formation. The filter cake provides further fluid loss control to the permeable formation.

Abstract: The present invention relates to a method of breaking an aqueous based viscosified fluid containing a breaker comprising an alkali metal chlorite or hypochlorite through use of a breaker activator comprising thioglycolate ion or a compound capable of producing thioglycolate ion in the aqueous fluid. The method is particularly effective in providing a controlled break in a treatment fluid introduced into a subterranean formation having a static temperature in the range of from about 100.degree. F. to about 200.degree. F.

Abstract: The present invention relates to a method of breaking an aqueous based viscosified fluid having potassium ions present therein with a breaker comprising an alkali metal chlorite or hypochlorite through use of a breaker activator comprising a source of ammonium ion in the aqueous fluid. The method is particularly effective in providing a controlled break in a treatment fluid introduced into a subterranean formation having a static temperature in the range of from about 100.degree. F. to about 300.degree. F. In some instances, a second breaker activator comprising a source of thioglycolate ion also may be admixed with the viscosified fluid to further accelerate breaker activation at temperatures below about 200.degree. F.

Abstract: The present invention relates to a pseudoplastic fluid composition including water, a mixed metal layered hydroxide dispersed in the water to impart preselected rheological properties to the fluid and a fluid loss additive composition including one or more of a carboxymethyl substituted vegetable starch, a carboxymethylated cellulosic compound or mixtures thereof in an amount effective to inhibit loss of fluid and with the degree of substitution being selected so that the carboxymethyl substituted compound is soluble in the fluid at the concentration of use without materially adversely affecting the rheological properties of the fluid and so that the fluid is resistant to fermentation. The improved composition includes a crosslinked carboxymethylated vegetable starch which has a degree of substitution in the broad range from about 0.3 to about 0.8 and in a narrower range of about 0.4 to about 0.

Abstract: A process for altering the permeability of a subterranean formation comprises injecting into the subterranean formation a gelling composition which comprises a carboxylate-containing polymer, a crosslinking agent, and a liquid such as a produced brine wherein the polymer forms a gel in the formation, in the presence of the crosslinking agent. The polymer can have a molecular weight of from about 10,000 to about 30,000,000, contain about 0.