Abstract: Apparatus and compositions for reducing the viscosity of a gelled fluid is provided. In one embodiment, a viscosity reducing microbe is disposed in a capsule and added to the gelled fluid. The gelled fluid may include a thickening agent adapted to increase its viscosity. Upon release from the capsule, the microbe begins to digest the thickening agent in the gelled fluid and/or releases enzymes that that breakdown the thickening agent.

Abstract: Methods and compositions of fracturing formations are provided. The fracturing fluid includes an enzyme breaker that decreases the viscosity of the fracturing fluid over time. The enzyme breaker can be used in environments having a pH value ranging from about 7 to about 12.

Abstract: The allosteric effectors, sulfate and phosphate, can be used with mannanohydrolase enzymes to better control the break of gelled fracturing fluids in wellbore operations. The fracturing fluid contains a hydratable polymer of guar, a guar derivative, a cellulose derivative, a water soluble biopolymer or a combination thereof and a crosslinking agent. The mannanohydrolase enzyme catalyzes the hydrolysis of ?-(1,4) mannosidic linkages to break the polymeric backbone.

Abstract: A composition and method for resolving reverse emulsions and complex water external emulsions using one or more polyepihalohydrins, one or more polyelectrolytes thereof, and any combination thereof is disclosed and claimed. The disclosed invention may be used in any crude oil production process where such emulsions are encountered.

Abstract: The present invention is directed to novel additives packages, to fluid compositions including the additives, to methods of using the fluid compositions and the additives package, to methods of recovering hydrocarbons, and to petroleum products made from hydrocarbons derived from these methods. The novel additives packages may be used in a fluid composition for fracturing a subterranean. The additives package of the present invention include one or more gelling agents; one or more cross-linking agent; and one or more high temperature stabilizers; wherein the additives package further comprises one or more ingredients selected from the group consisting of a clay stabilizer, a metallic base, a cross-link retarder, and a gel breaker, and any combination thereof; and wherein the additives package optionally includes a diluent.

Abstract: A method of cleaning a wellbore drilled with a drilling fluid that forms a filter cake that includes emplacing a breaker fluid into the wellbore, the breaker fluid comprising: an aqueous fluid; a fragmentation agent; and an amphoteric chemotrope; and shutting in the well for a period of time sufficient to initiate breaking of the filter cake is disclosed.

Abstract: A method for treating a subterranean formation includes forming a treatment fluid including a carrier fluid, a solid acid-precursor, and a solid scale inhibitor. The solid acid-precursor includes a material that forms an acid at downhole conditions in the subterranean formation. The method further includes adding a solid acid-responsive material into the treatment fluid, where the solid acid-responsive material enhances formation of acid from the solid acid-precursor in acidic conditions. The method includes performing an acid fracture treatment and inhibiting scale formation within the subterranean formation. The solid scale inhibitor allows for long-term scale inhibition after the treatment.

Abstract: Methods and compositions of fracturing formations are provided. The fracturing fluid includes an enzyme breaker that decreases the viscosity of the fracturing fluid over time. The enzyme breaker can be used in environments having a pH value ranging from about 7 to about 12.

Abstract: An aqueous fluid system that contains an aqueous dicarboxylic acid solution, a viscoelastic surfactant as a gelling agent to increase the viscosity of the fluid, and an internal breaker such as mineral oil and/or fish oil to controllably break the viscosity of the fluid provides a self-diverting acid treatment of subterranean formations. The internal breaker may be at least one mineral oil, a polyalphaolefin oil, a saturated fatty acid, and/or is an unsaturated fatty acid. The VES gelling agent does not yield viscosity until the organic acid starts to spend. Full viscosity yield of the VES gelling agent typically occurs at about 6.0 pH. The internal breaker allows the VES gelling agent to fully viscosify the spent organic acid at 6.0 pH and higher, but as the spent-acid VES gelled fluid reaching reservoir temperature, controllable break of the VES fluid viscosity over time can be achieved.

Abstract: Apparatus and methods of reducing the viscosity of a gelled fluid is provided. In one embodiment, a viscosity reducing microbe is disposed in a capsule and added to the gelled fluid. The gelled fluid may include a thickening agent adapted to increase its viscosity. Upon release from the capsule, the microbe begins to digest the thickening agent in the gelled fluid and/or releases enzymes that that breakdown the thickening agent.

Abstract: Fluids viscosified with viscoelastic surfactants (VESs) may have their viscosities reduced (gels broken) by the direct or indirect action of a composition that contains at least one metal ion source and optionally at least one second source. An optional second source may be a chelating agent where at least one reducing agent source may be additionally optionally used. Another optional component with the metal ion source includes a second, different metal ion source. The breaking composition is believed to directly attack the VES itself, possibly by disaggregating or otherwise attacking the micellar structure of the VES-gelled fluid, and/or possibly by changing the chemical structure of the VES to give two or more products.

Abstract: Compositions and methods are given for delayed breaking of viscoelastic surfactant gels inside formation pores, particularly for use in hydraulic fracturing. Breaking inside formation pores is accomplished without mechanical intervention or use of a second fluid. Acidic internal breakers such as sulfuric acid and nitric acid are used. The break may be accelerated, for example with a free radical propagating species, or retarded, for example with an oxygen scavenger.

Abstract: Fluids viscosified with viscoelastic surfactants (VESs) may have their viscosities reduced (gels broken) by the direct or indirect action of a composition that contains at least one metal ion source and optionally at least one second source. An optional second source may be a chelating agent where at least one reducing agent source may be additionally optionally used. Another optional component with the metal ion source includes a second, different metal ion source. The breaking composition is believed to directly attack the VES itself, possibly by disaggregating or otherwise attacking the micellar structure of the VES-gelled fluid, and/or possibly by changing the chemical structure of the VES to give two or more products.

Abstract: Delayed breakers are given that break viscoelastic surfactant fluids inside the pores of formations into which the fluids have been injected. The breakers comprise proteins, proteins that contain breakers, or cells that contain breakers. Proteins become breakers, and proteins and cells release breakers, due to a triggering mechanism that may be, for example, a change in temperature, pH, or salinity.

Abstract: The present invention relates to viscosified treatment fluids used in well completion and stimulation operations for oil and gas production, and more particularly, to viscosified treatment fluids comprising xanthan gelling agents. In one embodiment, the present invention provides a method of treating a portion of a subterranean formation comprising the steps of: providing a viscosified treatment fluid that comprises water and a gelling agent that comprises a modified xanthan; and treating the portion of the subterranean formation. The present invention also provides methods of fracturing, gravel packing, acidizing with the viscosified treatments fluids. Also provided are viscosified treatment fluid compositions and gelling agent compositions.

Abstract: Methods of treating a subterranean formation comprising providing a viscosified treatment fluid that comprises a base fluid and a gelling agent, providing a breaker composition that comprises an oxidizing breaker and a breaker activator that comprises a metal and a protein, allowing the viscosified treatment fluid to interact with the breaker composition, treating the subterranean formation with the viscosified treatment fluid, and allowing a viscosity of the viscosified treatment fluid to be reduced. Further, methods of reducing the viscosity of a viscosified treatment fluids and methods of activating oxidizing breakers are also provided.

Abstract: Improved methods and compositions for treating subterranean formations penetrated by well bores are provided. A method for breaking a gelled hydrocarbon fluid comprised of a hydrocarbon liquid, a ferric iron or aluminum polyvalent metal salt of a phosphonic acid ester or dialkylphosphinic acid is provided.

Abstract: Delayed breakers are given that break viscoelastic surfactant fluids inside the pores of formations into which the fluids have been injected. The breakers comprise proteins, proteins that contain breakers, or cells that contain breakers. Proteins become breakers, and proteins and cells release breakers, due to a triggering mechanism that may be, for example, a change in temperature, pH, or salinity.

Abstract: Improved methods for treating and for fracturing subterranean formations and the fluid compositions are provided. The viscosity of a treating fluid containing gelling agents is broken, even at temperatures of about 250° F. and lower, utilizing an oxidizing breaker and a reducing sugar to activate the breaker.

Abstract: An organic based emulsion-breaking formulation for use in treating well bores drilled in oil-bearing mud that is not eco-toxic and is optimally compatible with formation fluids comprises: as the emulsion-breaking agent, at least one constituent selected from non-ionic amphiphilic compositions obtained by reacting at least one polymerized vegetable oil with at least one aminoalcohol and alkyl esters (for example C1 to C8) of fatty acids derived from natural, vegetable or animal oils; optionally, at least one wetting agent selected from anionic surfactants; and optionally at least one solvent; the assembly being as a mixture in an organic base. Such a formulation can be weighted by mineral fillers.

Abstract: Improved methods for treating and for fracturing subterranean formations and the fluid compositions are provided. A method presented herein is a method of reducing the viscosity of a viscosified treatment fluid that comprises providing a viscosified treatment fluid that comprises a basic fluid and a gelling agent, providing a breaker composition comprising an oxidizing breaker and a breaker activator that comprises a reducing sugar; and allowing the breaker composition and the viscosified treatment fluid to interact so as to reduce the viscosity of the viscosified treatment fluid.

Abstract: It has been discovered that aminocarboxylic acids are effective breakers for polymer-gelled aqueous fracturing fluids, particularly in the temperature range between about 120° F. (49° C.) and about 280° F. (138° C.). The aminocarboxylic acids are believed to act directly on the polymer and not to any great extent or not to as an effective extent on a crosslinking agent, if present. The polymer may be a polysaccharide, and the aminocarboxylic acid may be selected from the group including, but not necessarily limited to, tetrasodium ethylenediaminetetraacetic acid (Na4EDTA), tetrasodium propylenediaminetetraacetic acid (Na4PDTA), trisodium hydroxyethylenediaminetetraacetic acid (Na4HEDTA), trisodium nitrilotriacetic acid (Na3NTA), salts of these acids, and mixtures thereof.

Abstract: In one embodiment, the present invention provides a method of reducing the viscosity of a viscosified treatment fluid comprising contacting the viscosified treatment fluid with an acid generated from an orthoester composition that comprises an orthoester. In another embodiment, the present invention provides a method of reducing the pH of a viscosified treatment fluid comprising providing an orthoester composition that comprises an orthoester; contacting the viscosified treatment fluid with the orthoester composition; allowing the orthoester to generate a generated acid; and allowing the generated acid to at least partially reduce the pH of the viscosified treatment fluid. Embodiments of fracturing and gravel packing methods also are disclosed.

Abstract: An oil-based demulsifying formulation which can be used in the treatment of drains bored in oil-based mud, non ecotoxic and optimally compatible with formation fluids, comprises at least one wetting agent chosen from anionic surfacetants and at least one demulsifier (or “emulsion breaker”) chosen from copolymers of ethylene oxide and propylene oxide, alcohol or phenol derivatives with alkoxylated or polyalkoxylated chain formations, polyalkyleneglycols, polyamines, alkoxylated or polyalkoxylated derivatives of amines, quaternary ammonium salts, quaternized alkanolamine esters, alkyl esters of fatty acids or natural oils, possible alkoxylated or polyalkoxylated, and silicated derivatives such as polysiloxanes.

Abstract: It has been discovered that fracturing fluid breaker mechanisms are improved by the inclusion of a polyol alone that directly degrades the polysaccharide backbone, and optionally additionally by removing the crosslinking ion, if present. That is, viscosity reduction (breaking) occurs by breaking down the chemical bonds within the backbone directly, rather than by merely removing the crosslinking ion, if present. The gel does not have to be crosslinked for the method of the invention to be successful, although it may be crosslinked. In one non-limiting embodiment, the polyol has at least two hydroxyl groups on adjacent carbon atoms. In another embodiment, the polyols are monosaccharides such as glycerols and sugar alcohols, and may include mannitol, sorbitol, glucose, fructose, galactose, mannose, lactose, maltose, allose, etc. and mixtures thereof.

Abstract: Methods and compositions for breaking treatment fluids utilized in the stimulation of a subterranean formation.

Abstract: A controlled-gelation aqueous solution is proposed. The solution contains a hydrophobically-aggregating gelling agent, and an effective amount of an inhibitor which suppresses hydrophobic aggregation of the gelling agent. The inhibitor is soluble in water so that when the controlled-gelation aqueous solution contacts aqueous media the inhibitor disperses and gelation occurs. However, the inhibitor is substantially insoluble in hydrocarbons so that when the controlled-gelation aqueous solution contacts hydrocarbon media the inhibitor continues to suppress said hydrophobic aggregation and gelation is suppressed. The solution may be used to control the flow of water into oil wells, making it possible to reduce the water cut.

Abstract: Methods of using invertible oil external-water internal emulsions in drilling, hydraulic fracturing, gravel packing and completion and then inverting the emulsion to a water external-oil internal emulsion are provided. The methods basically comprise the steps of contacting the oil external-water internal emulsion with an aqueous acid solution containing an anionic sulfonate surfactant for preventing aqueous acid solution-crude oil emulsions and crude oil sludging and a chemical for preventing the anionic sulfonate surfactant from reacting with the emulsifier in the oil external-water internal emulsion.

Abstract: Methods of treating subterranean zones and viscous aqueous fluids containing xanthan biopolymer gelling agent and a combination crosslinker and delayed breaker are provided. A viscous cross-linked aqueous treating fluid of the invention comprises water, a xanthan polymer gelling agent, and a combination cross-linker and delayed breaker for said xanthan biopolymer gelling agent.

Abstract: It has been discovered that fracturing fluid breaker mechanisms are improved by the inclusion of a catalyzed polyol alone that directly degrades the polysaccharide backbone, and optionally additionally by removing the crosslinking ion, if present. That is, viscosity reduction (breaking) occurs by breaking down the chemical bonds within the backbone directly. The gel does not have to be crosslinked for the method of the invention to be successful, although it may be crosslinked. In one non-limiting embodiment, the polyol has at least two hydroxyl groups on adjacent carbon atoms. In another embodiment, the polyols are simple sugars and sugar alcohols, and may include mannitol, sorbitol, glucose, fructose, galactose, mannose, lactose, maltose, allose, etc. and mixtures thereof. The catalyzing metal ion may employ a metal selected from Groups VIB, VIIB, VIII, IB, and IIB of the Periodic Table (previous IUPAC American Group notation).

Abstract: It was found that the addition of polymers to viscoelastic surfactant base system allows to adjust the rheological properties of the base fluid. Depending in particular on one side of the ratio of the concentration of added polymer and the concentration of viscoelastic surfactant and on the other side of the molecular weight of the added polymer, the same polymer—or the same type of polymer—may perform different functions such as viscosity enhancer, viscosity breaker or viscosity-recovery enhancer.

Abstract: It has been discovered that biodegradable and non-toxic chelant compositions can perform multiple beneficial functions in an aqueous fracturing fluid through the chelation of ions. Some of the multiple functions include various combinations of the following: demulsifier, demulsifier enhancer, scale inhibitor, crosslink delay agent, crosslinked gel stabilizer, enzyme breaker stabilizer, and the like. Some of the chelants used in the compositions include, but are not necessarily limited to, sodium polyaspartate; sodium iminodisuccinate; disodium hydroxyethyleneiminodiacetate (Na2HEIDA); sodium gluconate; sodium glucoheptonate; sugar alcohols; monosaccharides; disaccharides; and mixtures thereof.

Abstract: Improved methods and compositions for consolidating proppant in fractures formed in subterranean zones are provided. An improvement of this invention comprises using proppant particles having a coating of hardenable resin including a gel breaker. The gel breaker facilitates removal of gelled carrier fluid from the surface of the proppant particles.

Abstract: Method of treating a subterranean formation, comprising (A) injecting down a well bore into the formation an admixture of (a) an emulsion having an internal aqueous phase comprising a water-soluble oil of gas field chemical or an aqueous dispersion of a water-dispersible oil or gas field chemical and an external oil phase comprising a liquid hydrocarbon and an oil-soluble surfactant and (b) a demulsifier comprising a solution of a surfactant having a cloud point temperature of above 40° C. Alternatively, the method comprises separately injecting down a well bore into the formation emulsion (a) and demulsifier (b) and generating an admixture of emulsion (a) and demulsifier (b) within the formation.

Abstract: A method of fracturing subterranean zones at temperature below about 200° F. wherein the fracturing fluid comprises water, a viscosity increasing gelling agent, a particulate proppant material, a delayed viscosity breaker for causing the fracturing fluid to revert to a thin fluid and a breaker activator comprising a mixture selected from the group of a mixture of cobaltous acetate and the sodium salt of ethylenediaminetetraacetic acid and a mixture of thioglycolic acid and sodium molybdate.

Abstract: Methods and compositions effective for preventing or resolving emulsions of oil in aqueous solutions, preferably for preventing or resolving oil-in-water emulsions formed in aqueous brines used as completion fluids or workover fluids.

Abstract: The present invention provides seawater-based cross-linked fracturing fluids and methods of preparing and using the fluids in fracturing subterranean formations penetrated by well bores and having temperatures above about 200° F. The improved cross-linked fracturing fluids are basically comprised of a gelling agent, seawater present in an amount sufficient to hydrate the gelling agent and to form a gelled aqueous fluid, and a delayed cross-linking agent, capable of causing delayed cross-linking of the gelling agent in the gelled aqueous fluid at a pH below the threshold for precipitate formation in seawater.

Abstract: Methods and compositions are disclosed for controlled addition of components that decrease the viscosity of the viscoelastic surfactant fluids or for controlled changes in the electrolyte concentration or composition of the viscoelastic surfactant fluids. One aspect of the invention relates to the use of internal breakers with a delayed activation. Another aspect of the invention relates to the use of precursors that release a breaking system such as alcohol by a process such as melting, slow dissolution, reaction with a compound present in the fluid or added to the fluid during or after the step of injecting, rupture of an encapsulating coating and de-adsorption of a breaking agent absorbed into solid particles. In another aspect of the invention, alcohols are included in a pad to reduce the low-shear viscosity and reduce the resistance to flow of the treatment fluids during a desired phase of the treatment.

Abstract: Methods and compositions are disclosed for controlled addition of components that decrease the viscosity of the viscoelastic surfactant fluids or for controlled changes in the electrolyte concentration or composition of the viscoelastic surfactant fluids. One aspect of the invention relates to the use of internal breakers with a delayed activation. Another aspect of the invention relates to the use of precursors that release a breaking system such as alcohol by a process such as melting, slow dissolution, reaction with a compound present in the fluid or added to the fluid during or after the step of injecting, rupture of an encapsulating coating and de-adsorption of a breaking agent absorbed into solid particles. In another aspect of the invention, alcohols are included in a pad to reduce the low-shear viscosity and reduce the resistance to flow of the treatment fluids during a desired phase of the treatment.

Abstract: A wellbore fluid including a peroxide degradable polymer and an encapsulated peroxide source. The peroxide degradable polymer may be a polysaccharide. The peroxide source may include an inorganic peroxide, including zinc and alkaline earth metal peroxides, such as magnesium peroxide. The encapsulating material may be a polymer, including enteric polymers. The release of peroxide, from peroxide sources generally, can be controlled by means of pH such that peroxide source can be activated, and peroxide released, by a change in pH. In a wellbore, this pH change can be effected by using produced fluids to lower the pH of a more basic wellbore fluid.

Abstract: There is described a fracturing fluid comprising a polar base, 0.1-5.0% of a mid-molecular weight polyacrylate, and an activator for ionizing the polyacrylate to a hydroscopic state.

Abstract: Coatings for well screens that protect the screens from damage as they are inserted into the wellbore and once in the well, release reactive materials to react with and degrade potentially plugging materials such as drill solids, fluid filtercakes, fluid loss additives, and drilling fluids. The coatings can be specifically designed for individual well conditions and are comprised of a binder that either melts or dissolves within the wellbore and one or more reactive materials such as acids, enzymes, surfactants, chelants, oxidizers or free radical generators and the like which are released into the screen and the near wellbore area and which are effective in degrading or dissolving materials which could potentially plug the screen.

Abstract: Disclosed are methods and related compositions for altering the physical and chemical properties of a substrate used in hydrocarbon exploitation, such as in downhole drilling operations. In a preferred embodiment a method involves formulating a fluid, tailored to the specific drilling conditions, that contains one or more inactivated enzymes. Preferably the enzyme is inactivated by encapsulation in a pH responsive material. After the fluid has been introduced into the well bore, one or more triggering signals, such as a change in pH, is applied to the fluid that will activate or reactivate the inactivated enzyme, preferably by causing it to be released by the encapsulation material. The reactivated enzyme is capable of selectively acting upon a substrate located downhole to bring about the desired change in the chemical or physical properties of the substrate.

Abstract: A low residue well treatment fluid comprises: an aqueous solvent; a gelling agent comprising one or modified polysaccharides, the modified polysaccharides having hydrophilic groups; and a crosslinking composition. The fluid may optionally further comprise a gel breaker, a buffer and/or a proppant. The fluids generate no or minimal residue upon being broken, and are particularly useful in well fracturing operations.

Abstract: This invention provides methods of fracturing subterranean zones, fracturing fluids and breaker activators for use in the fracturing fluids. The fracturing fluids are basically comprised of water, a gelling agent, a particulate proppant material, a delayed viscosity breaker and a breaker activator.

Abstract: The present invention provides methods of treating subterranean zones penetrated by well bores in primary well cementing operations, well completion operations, production stimulation treatments and the like. The methods are basically comprised of introducing into the subterranean zone an aqueous well treating fluid comprised of water and a water soluble polymer complex fluid loss control additive.

Abstract: The present invention relates to biodegradable chemical compositions wherein core substrates, particularly oil well chemicals, are adsorbed onto particulate starch, particularly granular starch, providing a stable, controlled release formulation suitable for use in oil field applications. The invention further relates to the process of preparing obtaining these compositions.

Abstract: It has been discovered that aminocarboxylic acids are effective breakers for polymer-gelled aqueous fracturing fluids, particularly in the temperature range between about 120° F. (49° C.) and about 280° F. (138° C.). The aminocarboxylic acids are believed to act directly on the polymer and not to any great extent or not to as an effective extent on a crosslinking agent, if present. The polymer may be a polysaccharide, and the aminocarboxylic acid may be selected from the group including, but not necessarily limited to, tetrasodium ethylenediaminetetraacetic acid (Na4EDTA), tetrasodium propylenediaminetetraacetic acid (Na4PDTA), trisodium hydroxyethylenediaminetetraacetic acid (Na4HEDTA), trisodium nitrilotriacetic acid (Na3NTA), salts of these acids, and mixtures thereof.

Abstract: The present invention provides seawater-based cross-linked fracturing fluids and methods of preparing and using the fluids in fracturing subterranean formations penetrated by well bores and having temperatures above about 200° F. The improved cross-linked fracturing fluids are basically comprised of a gelling agent, seawater present in an amount sufficient to hydrate the gelling agent and to form a gelled aqueous fluid, and a delayed cross-linking agent, capable of causing delayed cross-linking of the gelling agent in the gelled aqueous fluid at a pH below the threshold for precipitate formation in seawater.

Abstract: It has been discovered that borate crosslinked fracturing fluid breaker mechanisms are improved by the inclusion of a polyol together with an enzyme. In fact, synergistic results may be achieved when both are used together as contrasted to the cases where each are used separately. Removing the borate ion from the crosslinked polymer reduces the pH of the fluid and in turn increases the activity of the enzyme. That is, once the pH is lowered, viscosity reduction (breaking) occurs by uncrosslinking of the polymer within the fracturing fluid, and by initiating or increasing activity of an enzyme breaker, if present. In one embodiment, the polyol has at least two cis-hydroxyl groups. In another embodiment, the polyols are monosaccharides such as glycerols and sugar alcohols, and may include mannitol, sorbitol, glucose, fructose, galactose, mannose, allose, etc. and mixtures thereof. Oligosaccharides and derivatives of monosaccharides and oligosaccharides are also useful.