Abstract: A non-aqueous suspension including boron-containing particulates, a low molecular weight polyalkylene glycol and a suspension stabilizer is provided. Methods of crosslinking water soluble polymers and of fracturing a subterranean formation are also provided.

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: Disclosed is a concentrate composition for crosslinking polysaccharide polymers hydrated in an aqueous liquid, and well servicing fluids, preferably fracturing fluids, prepared therewith. Preferred polysaccharide polymers are galactomannan gums or derivatives thereof, preferably hydroxypropylguar. The concentrate comprises an alkali metal formate solution, preferably potassium formate, a crosslinking agent for the polysaccharide polymer, preferably a sparingly soluble alkali metal or alkali metal alkaline earth metal borate, and a suspension agent, preferably a clay mineral selected from the group consisting of smectite clays, palygorskite clays, and mixtures thereof Exemplary clays are hectorite, sepiolite, and attapulgite. The concentrate may, optionally, contain a deflocculant and/or an anti-syneresis additive.

Abstract: Methods are provided for fracturing subterranean formations using fluids having substantially reduced polymer loadings that have performance equivalent to conventional fluids. Reduced polymer loadings provide significant advantages such as reduced treatment costs and less damage to the fracture sand pack and surrounding subterranean formations.

Abstract: The present invention relates to methods and compositions for treating subterranean well formations, and more specifically, to improved subterranean formation treating fluid concentrates, treating fluids and methods of using such treating fluids in subterranean formations. The treating fluid concentrates generally comprise water and a substantially fully hydrated depolymerized polymer. The treating fluids which are formed by adding water to the treating fluid concentrates generally comprise water, a substantially fully hydrated depolymerized polymer and a crosslinking agent for crosslinking the hydrated depolymerized polymer.

Abstract: The present invention relates to increasing the permeability of a subterranean formation by forming a resinous mass having conductive channels through which fluids can be produced in the formation. Some embodiments of the present invention provide methods of creating a permeable resinous mass comprising the steps of selecting an interval along a well bore; providing a resin slurry comprising an acid curable resin, filler, and degradable material; placing the resin slurry into the selected interval; and, activating the acid curable resin using an activator wherein the activation causes the acid curable resin to substantially cure, the degradable material to substantially degrade, and forms the permeable resinous mass.

Abstract: The present invention provides improved methods of fracturing subterranean zones penetrated by well bores and improved fracturing fluids. The fracturing fluids are basically comprised of water, a terpolymer of 2-acrylamido-2-methylpropane sulfonic acid, acrylamide and acrylic acid, or its salts, a cross-linking agent for the terpolymer and a delayed viscosity breaker for effecting a controlled reduction in the viscosity of the fracturing fluid.

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

Abstract: The invention provides an aqueous suspension/concentrate of a sparingly soluble borate, preferably as disclosed in Mondshine U.S. Pat. No. 4,619,776, which is effective in crosslinking aqueous solutions of a water soluble, borate-crosslinkable polymer, preferably guar gum and derivatives thereof. The aqueous suspension/concentrate comprises a saturated aqueous solution of a sparingly soluble borate, a suspension agent, suspended particles of a sparingly soluble borate, and optionally a stabilizing agent, wherein the saturated solution of the sparingly soluble borate is prepared prior to the particles of the sparingly soluble borate being suspended therein. The preferred suspension agent is a palygorskite clay such as attapulgite and sepiolite. The invention further provides a method of hydraulically fracturing a formation with the aqueous borate suspension/concentrate.

Abstract: The present invention provides a cement composition and a process for using the cement composition to inhibit gas migration from a subterranean zone into the cement. The process comprises displacing a gelling additive, preferably comprised within a cement composition, into a well bore such that the gelling additive passes into the subterranean zone, and allowing the gelling additive to form a crosslinked gel in the subterranean zone to inhibit gas migration from the subterranean zone. The crosslinked gel acts as a barrier to gas in the subterranean zone and thereby inhibits the gas from passing into the cement and forming flow channels therein before the cement can set.

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 filter aid, and optionally, a reinforcing material preferably 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: 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: For tubing/casing annulus plug treatment to plug a well, a tubing/casing annulus 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 tubing/casing annulus plug fluid includes contacting the additive with water or an aqueous solution, with a method of plugging the tubing/casing annulus of a well further including the step of injecting the fluid into the annulus.

Abstract: Disclosed is a copolymer useful for preparing acid gels comprising a copolymer having a copolymer backbone, the copolymer having a general formula: wherein: (a) A is an H or other terminating group; (b) R1 is an OH or NH2; (c) R2 is an O or NH; (d) Z is an integer having a value of from 1 to 4; (e) X and Y are present in a ratio (X:Y) of from 3:2 to 4:1; (f) structures I and II are present as blocks or randomly distributed along the copolymer backbone; and wherein the copolymer has a molecular weight of from about 1,000,000 to about 10,000,000.

Abstract: Methods of forming chemical casings include drilling a well bore with a drilling fluid having a pH in the range of from about 6 to 10 and comprising water, a water soluble or water dispersible polymer which is capable of being cross-linked by a thermoset resin and causing the resin to be hard and tough when cured, a particulate curable solid thermoset resin, a water soluble or dispersible thermoset resin, and a delayed dispersible acid-catalyst for curing the solid thermoset resin and the water soluble thermoset resin, whereby the drilling fluid forms a filter cake on the walls of the wellbore that cures into a hard and tough cross-linked chemical casing thereon.

Abstract: Fracturing fluid compositions and methods for their preparation and use are disclosed. The compositions are useful in the oil and gas drilling operations, as well as in gravel packing operations, water blocking, temporary plugging for purposes of wellbore isolation and/or fluid loss control, and other uses. The compositions comprise a liquid, a polymer soluble in the liquid, having a degree of substitution of ionic groups of about 0.01 to about 0.1; and a crosslinking agent capable of increasing the viscosity of the fracturing fluid by crosslinking the polymer in liquid.

Abstract: Methods of consolidating formations include drilling a well bore with a drilling fluid that comprises water, a polymeric cationic catalyst which is adsorbed on minerals and rocks in weak unconsolidated zones or formations and then further contacting the unconsolidated formation with a treating fluid comprising a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, and a water soluble or dispersible thermoset resin which cross-links the polymer, is catalyzed and cured by the catalyst and consolidates the weak zone or formation so that sloughing is prevented.

Abstract: Methods of consolidating unconsolidated weak zones or formations and forming chemical casings include drilling a well bore with a drilling fluid having a pH in the range of from about 6 to 10 and that comprises water, a polymeric cationic catalyst which is adsorbed on the mineral surfaces in the weak zone, a particulate curable solid thermoset resin and a delay acid catalyst for curing the solid resin, and forming a filter cake on the walls of the well bore. The filter cake is then contacted with a treating fluid comprising a water soluble or water dispersible polymer which is capable of being cross-linked by a thermoset resin and causing the resin to be hard and tough when cured, and a water soluble or dispersible thermoset resin, whereby the treating fluid components deposit on the filter cake and the thermoset resin cures into a hard and tough cross-linked chemical casing thereon.

Abstract: Methods of treating subterranean zones penetrated by well bores wherein the static temperatures of the zones are as high as 400° F. and greater include using aqueous treating fluids comprised of an aqueous liquid containing one or more inorganic monovalent salts, multivalent salts or both in an amount no greater than about 5% by weight of the aqueous liquid and one or more specific synthetic hectorite clay gelling and thixotropy imparting agents.

Abstract: The present invention related to a method for fracturing subterranean formations including the steps of (a) providing a water source; (b) adding a crosslinking agent to said water source; (c) adding a polymeric component to said water to create a fracturing fluid; (d) pumping said fracturing fluid into said formation. The fluid may contain an acrylamide-acrylate copolymer and any suitable number of additives. The additives are preferably combined with the water source to form an additive stream, to which the polymer is later added.

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 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 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: The present invention provides xanthan gels hydratable in brine, methods of making these xanthan gels, and methods of using these compositions in subterranean formation applications, such as gravel packing.

Abstract: Well-working fluid compositions containing certain processed inorganic, oil and water wettable ground elastomeric crumb rubber materials to decrease the seepage loss of various fluids to subterranean formations in which these well working fluids are required and utilized are disclosed. Also disclosed is a method of reducing the seepage and whole mud loss of these well working fluids utilizing such ground elastomeric crumb rubber materials.

Abstract: The present invention provides a well treatment fluid containing water, a amine-based polymer, and an oxidized polysaccharide-based polymer. The oxidized polysaccharide-based polymer is able to crosslink with the amine-based polymer and produce a gel having a viscosity of greater than about 20 cp, measured at a pH of about 4 to about 7 and at STP. The present invention also provides a method of treating a subterranean formation penetrated by a wellbore comprising the steps of: (a) forming the well treatment fluid, and (b) contacting the subterranean formation with the fluid.

Abstract: A method is disclosed for drilling a wellbore employing a drilling fluid providing the advantages of easy pumpability of a low viscosity fluid with the drill cuttings suspension capability of a highly viscous fluid. The viscosity of the fluid is also easily and quickly adjustable so that the fluid rheology may be adapted during drilling as the subterranean conditions change. These advantages are obtained by including in said fluid a reversibly crosslinkable polymer and an encapsulated crosslink activator. The crosslink activator causes crosslinking after the fluid is in the wellbore. The crosslinking is reversed at the well surface to reduce the viscosity of the fluid to enable the drill cuttings to be easily removed. Crosslink activator is added back to the fluid and the fluid is returned to the borehole. The amount of crosslink activator and/or crosslinkable polymer may be adjusted in the fluid to change the fluid rheology to conform the fluid to changes in the well conditions as monitored real time.

Abstract: Methods of fracturing subterranean zones to produce maximum hydrocarbon productivity are provided. The methods are basically comprised of providing a fracturing fluid comprised of water, a gelling agent present in an amount in the range of from about 0.06% to about 0.3% by weight of the water and an inorganic salt for preventing clay swelling present in an amount in the range of from about 0.01% to about 1% by weight of the water. The fracturing fluid is introduced into the subterranean zone at a rate and pressure sufficient to form fractures and the fracturing fluid is recovered from the zone.

Abstract: Methods and compositions for sealing subterranean zones having temperatures in the range of from about 80° F. to about 300°F. are provided. A method of the invention is basically comprised of the steps of providing a subterranean zone sealing composition that becomes substantially rigid when exposed to subterranean zone temperatures above about 80° F. and has a pH above about 8.5 comprised of water, a substantially fully hydrated depolymerized polymer and a cross-linking agent. The sealing composition is introduced into the subterranean zone whereby it becomes rigid and seals the zone. The sealing composition can subsequently be removed by contact with a fluid having a pH below about 8 when a boron compound is utilized as the cross-linking agent.

Abstract: A well service fluid composition comprises a fracturing fluid and a gas hydrate inhibitor. Preferably, the gas hydrate inhibitor does not affect the function of the fracturing fluid and is present in an amount sufficient to control and/or minimize the formation of gas hydrates. The well service fluid composition is useful in hydraulic fracturing in which the composition is injected into a subterranean formation under sufficient pressure to initiate and propagate a fracture in the formation. The fracturing fluid may be subsequently recovered when the fracturing operation is completed.

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: The present invention provides environmentally safe foamed fracturing fluids, additives for foaming and stabilizing foamed fracturing fluids and methods of fracturing subterranean zones. The foamed fracturing fluids of this invention are basically comprised of water, a gelling agent for forming the water into gelled water and increasing the viscosity thereof, sufficient gas to form a foam, and an effective amount of an additive for foaming and stabilizing the gelled water comprised of hydrolyzed keratin.

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: Methods of consolidating formations or forming chemical casing or both while drilling are provided. One method of the invention comprises drilling a well bore with a drilling fluid comprised of water, a polymeric cationic catalyst which is adsorbed on weak zones or formations formed of unconsolidated clays, shale, sand stone and the like, a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, a particulate curable solid thermoset resin, a water soluble thermoset resin, and a delayed dispersible acid catalyst for curing the solid and water soluble resins. The drilling fluid forms a filter cake on the walls of the well bore that cures and consolidates the unconsolidated weak zones and formations penetrated by the well bore so that sloughing is prevented and forms a hard and tough cross-linked chemical casing on the walls of the well bore.

Abstract: Compositions and methods are provided for reducing the permeability of subterranean zones. More particularly, water-soluble polymeric compositions which form cross-linked gels in the zones. In general, the composition comprises (a) at least one water-soluble polymer; (b) at least one organic gelling agent capable of cross-linking the water-soluble polymer; and (c) at least one water-soluble formate. More preferably, the water-soluble polymer is a copolymer of (i) at least one non-acidic ethylenically unsaturated polar monomer, and (ii) at least one copolymerisable ethylenically unsaturated ester. The gelling agent is preferably selected from the group consisting of a polyalkyleneimine, polyfunctional aliphatic amine, an aralkylamine, and a heteroaralkylamine. The preferred water-soluble formate is selected from the group consisting of ammonium formate, lithium formate, sodium formate, potassium formate, rubidium formate, cesium formate, and francium formate.

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 filter aid, and optionally, a reinforcing material preferably 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: For conformance treatment to plug an opening in subterranean hydrocarbon bearing formation, a conformance additive including water soluble crosslinkable polymer, a crosslinking agent, a filter aid that is preferably diatomaceous earth, and optionally a reinforcing material. 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 formation treating fluid comprises one or more borate esters, a liquid carrier and, one or more cross linkable polymer wherein the formation treating fluid has an alkaline pH when the formation treating fluid is positioned in a formation. The formation treating fluid is useful in high temperature operations such as hydraulic fracturing.

Abstract: A swellable polymer gel composition for use in subterranean formations. The composition comprises water, a water soluble polymer, a water soluble crosslinking system and a swelling agent. The crosslinking system may be either a redox system or a chelating system. The amounts of the polymer and the crosslinking system are effective to form a substantially uniformly reacted tri-dimensional gel structure. To the gel solution, is added a swelling agent in an amount sufficient to increase the volume of the gel a predetermined percentage. The swelling agent may be a natural or a synthetic agent. A strengthening agent may be added to increase the gel strength of the composition. The composition has numerous uses and is particularly useful in oil industry applications such as plugging wells, sealing casing leaks and reducing water production from water-bearing hydrocarbon formations.

Abstract: Methods of consolidating formations or forming chemical casing or both while drilling are provided. One method of the invention comprises drilling a well bore with a drilling fluid comprised of water, a polymeric cationic catalyst which is adsorbed on weak zones or formations formed of unconsolidated clays, shale, sand stone and the like, a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, a particulate curable solid thermoset resin, a water soluble thermoset resin, and a delayed dispersible acid catalyst for curing the solid and water soluble resins. The drilling fluid forms a filter cake on the walls of the well bore that cures and consolidates the unconsolidated weak zones and formations penetrated by the well bore so that sloughing is prevented and forms a hard and tough cross-linked chemical casing on the walls of the well bore.

Abstract: The present invention provides methods of treating subterranean zones penetrated by well bores wherein the static temperatures of the zones are as high as 400° F. and greater. The aqueous treating fluids are basically comprised of an aqueous liquid containing one or more inorganic monovalent salts, multivalent salts or both in an amount no greater than about 5% by weight of said aqueous liquid and one or more synthetic hectorite clay gelling and thixotropy imparting agents selected from the group of a synthetic hectorite clay having the composition by weight on a dry basis of 59.5% SiO2, 27.5% MgO, 0.8% Li2O and 2.8% Na2O, a synthetic hectorite clay having the composition by weight on a dry basis of 54.5% SiO2, 26.0% MgO, 0.8% Li2O, 5.6% Na2O and 4.1% P2O5 and a synthetic hectorite clay having the composition by weight on a dry basis of 54.5% SiO2, 26.0% MgO, 0.8% LiO2, 5.6% Na2O, 4.1% P2O5 and also containing inorganic polyphosphate peptizers.

Abstract: Methods are provided for fracturing subterranean formations using fluids having substantially reduced polymer loadings that have performance equivalent to conventional fluids. Reduced polymer loadings provide significant advantages such as reduced treatment costs and less damage to the fracture sand pack and surrounding subterranean formations.

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 cation-releasing material. When cations are released or liberated within the fracturing fluid, they complex with the hydroxide or carbonate pH buffers used within the borate crosslinked fracturing fluid, which in turn reduces the pH of the fracturing fluid. 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 cations are divalent cations. The divalent cations are preferably slowly released over a period of time. Two specific, preferred materials for releasing divalent cations are calcium lignosulfonate and calcium chloride, the latter preferably in encapsulated form.

Abstract: The present invention related to a method for fracturing subterranean formations including the steps of (a) providing a water source; (b) adding a crosslinking agent to said water source; (c) adding a polymeric component to said water to create a fracturing fluid; (d) pumping said fracturing fluid into said formation. The fluid may contain an acrylamide-acrylate copolymer and any suitable number of additives. The additives are preferably combined with the water source to form an additive stream, to which the polymer is later added.

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.

Abstract: Methods of forming permeable sand screens in long, open hole well bores within fluid producing zones are provided by the present invention. The methods basically comprise the steps of placing a perforated pipe in the open hole well bore, providing a hardenable composition which after being placed in a desired location cures into a hard mass, placing said hardenable composition in said well bore adjacent to said fluid producing zone within the interior of the perforated pipe therein, between the perforated pipe and the walls of the open hole well bore and within voids or fractures in the producing zone, causing the hardenable composition to cure into a hard permeable mass and drilling the hard permeable mass out of the interior of the perforated pipe.

Abstract: The present invention provides methods of preventing the flow of water or gas or both through a subterranean zone having a high temperature and a depth such that a long pumping time is required to place a sealing composition therein. The methods basically comprise the steps of preparing a polymeric sealing composition comprised of water, a cross-linking agent and a selected water-soluble polymer which reacts with the cross-linking agent and forms a sealing gel which is stable for a desired period of time at the temperature of the zone and has a pumping time before gelation in the presence of the cross-linking agent whereby the composition can be pumped to the depth of the zone and placed therein. Thereafter, the sealing composition is pumped into the zone and allowed to form a sealing gel therein.

Abstract: Herein is disclosed a well completion or stimulation fluid, comprising (i) a carrier fluid; (ii) a viscoelastic surfactant; and (iii) a fluid loss control additive (FLA) comprising at least one polymer and at least one crosslinker. The fluid may further comprise proppant or gravel, if it is intended for use as a fracturing fluid or a gravel packing fluid, although such uses do not require that the fluid comprise proppant or gravel. Also disclosed herein are methods of fracturing a subterranean formation, comprising (i) providing a fracturing fluid discussed above and (ii) injecting the fracturing fluid into the formation at a pressure sufficiently high to fracture the formation. In addition, disclosed herein are methods of gravel packing a wellbore, comprising (i) providing a gravel packing fluid discussed above and (ii) injecting the gravel packing fluid into the wellbore.