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: Alcohol based hydraulic fracturing fluids useful for treating oil and gas wells are disclosed. The fluids are compatible with carbon dioxide, and comprise an alcohol, a polymer, a crosslinking agent, and a breaker. Hydroxypropyl guar with a molar substitution of about 1.2 to about 2.2 is identified as a presently preferred polymer.

Abstract: The present invention generally relates to compositions of matter and methods of using those compositions. More particularly, and as part of one of the preferred embodiments, the present invention relates to compositions and methods of use of fluids useful for sealing formation fractures and/or inhibiting downhole fluid loss. The present invention is useful as a pill or series of pills that can be formulated and spotted to a particular formation zone.

Abstract: 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, are provided herein.

Abstract: Methods of treating subterranean zones and high density viscous aqueous treating fluids are provided. A high density viscous aqueous treating fluid of the invention comprises salt water comprising water and one or more oxidation resistant salts; a gelling agent; and a delayed oxidizing gel breaker.

Abstract: Viscous well treating fluids and methods of treating subterranean zones penetrated by well bores are provided. The viscous fluids are basically comprised of water, a gelling agent and a delayed viscosity breaker comprising pentanedione peroxide.

Abstract: Methods and compositions for treating subterranean zones penetrated by well bores utilizing environmentally safe viscous fluids including a solubility increasing boron complex or ester forming compound. A method of the invention comprises the following steps. A viscous treating fluid composition is provided comprising water, a viscosity increasing polymer and a water soluble delayed polymer breaker that comprises a mixture of sodium perborate tetrahydrate and a solubility increasing boron complex or ester forming compound. The viscous treating fluid composition is introduced into the subterranean zone wherein the viscous treating fluid is allowed to break into a thin fluid of reduced viscosity.

Abstract: The present invention provides oil based compositions and methods of using the compositions for temporarily sealing subterranean zones. The compositions are basically comprised of oil, a hydratable polymer, an organophilic clay, a water-swellable clay, and an acid soluble material such as calcium carbonate. These compositions will form a viscous gel when contacted with water. The gelled mass may then be dissolved with an acidic fluid, such as 15% hydrochloric acid.

Abstract: Well completion foamed spacer fluids and methods of using the foamed spacer fluids are provided. A method of the invention for displacing a first fluid from a well bore with an incompatible second fluid comprises the following steps. A foamed spacer fluid is placed between the first and second fluids to separate the first and second fluids and to remove the first fluid from the walls of the well bore. Thereafter, the first fluid and the foamed spacer fluid are displaced from the well bore with the second fluid.

Abstract: A storable cement system comprises a suspending agent, a cement spacer and water. The composition may further optional contain a surfactant and/or an organic solvent and/or a weighting material. The suspending agent is preferably a carrageenan or scleroglucan. The cement system may be stored for an extended period of time prior to being interposed between a cement slurry and a drilling fluid. As such, the aqueous cement system may be made off-site and used when desired for preventing contact between non-compatible hydrocarbonaceous and aqueous fluids.

Abstract: Methods of fracturing subterranean zones with less pumping are provided. The methods basically comprise the steps of providing an aqueous fracturing fluid comprised of a brine having a density in the range of from about 9 to about 19 pounds per gallon, pumping the aqueous fracturing fluid into the subterranean zone at a rate and pressure sufficient to fracture the subterranean zone and recovering the aqueous fracturing fluid from the subterranean zone.

Abstract: Liquid water soluble polymer suspensions in non-aqueous solvents are extremely stable over long periods of time with minimum separation of the solvent and no hard packing of the dispersed water soluble polymer. The suspensions enable a user to rapidly add the suspension to water, being mixed at low speeds, without the formation of lumps or fisheyes and without generating fugitive dust in the process. The suspensions are environmentally safe and biodegradable. Unlike many other liquid polymer suspensions, the suspensions exhibit minimal oil or grease upon dilution. They contain no surfactants that can add to the oil and grease determination. The suspensions and the fluids produced by diluting the fluids to a working concentration of the water soluble polymer exhibit low toxicity to marine organisms and to humans. The suspensions can be manufactured from ingredients suitable for use in personal care applications such as cosmetics, shampoos and the like.

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: Disclosed is a hydrophilic, water soluble polymer concentrate for addition to aqueous liquids to enhance the properties thereof, particularly to increase the viscosity or decrease the fluid loss of well drilling and servicing fluids, the concentrate comprising a hydrophobic, water insoluble liquid, an organophilic clay suspension agent, the water soluble polymer, and a stabilizing agent comprising one or more acids in an amount from about 0.001% to about 1.5%, one or more anionic surfactants in an amount from about 0.001% to about 1.0%, one or more nonionic surfactants in an amount from 0.001% to about 0.625% and, from about 0% to about 0.75% of one or more water soluble organic liquids, wherein the total concentration of the stabilizing agent is from about 0.1% to about 2.5%, these percentages being based on the weight of the concentrate.

Abstract: A method of treating a well including injecting a thermally stable, substantially water-free well-treating fluid into the well, wherein the well-treating fluid comprises a polymer, a glycol compound, and a salt is disclosed. In another embodiment, a thermally stable, substantially water-free well fluid including a polymer, a diol compound, and a salt is disclosed.

Abstract: The invention provides a method and fluid for drilling or servicing a well in a subterranean formation containing lost circulation zones or depleted, low pressure reservoirs. The fluid comprises an aqueous liquid having dispersed therein a viscosifier which increases the low shear rate viscosity of the fluid to at least 10,000 centipoise, an aphron-generating surfactant, and aphrons, wherein the fluid contains less than about 20% by volume of aphrons preferably generated by the turbulence and pressure drop as the fluid exits the drill bit in the vicinity of the formation. The method of drilling a wellbore in a subterranean formation comprises continuously re-circulating, while drilling, such a drilling fluid.

Abstract: A well fracturing fluid comprising one or more anionic viscoelastic surfactants and one or more polymers is described. The fluids can contain an aqueous or non-aqueous fluid and/or buffer for adjusting the pH of the fracturing fluid. The well service fluid can used as a fracturing fluid in order to control water production from a well, while simultaneously increasing the oil production from the well.

Abstract: The present invention generally relates to compositions of matter and methods of using those compositions. More particularly, and as part of one of the preferred embodiments, the present invention relates to compositions and methods of use of fluids useful for sealing formation fractures and/or inhibiting downhole fluid loss. The present invention is useful as a pill or series of pills that can be formulated and spotted to a particular formation zone.

Abstract: Well drilling and servicing fluids for use in producing formations and methods of removing filter cake therefrom are provided. The methods basically comprise using a drilling or servicing fluid comprised of water, a density increasing water soluble salt, a fluid loss control agent, a hydratable polymer solid suspending agent and a particulate solid bridging agent which is soluble in an aqueous ammonium salt solution. Thereafter, the filter cake deposited by the drilling or servicing fluid is contacted with a clean-up solution comprised of water and an ammonium salt for a period of time such that the bridging agent is dissolved thereby.

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: Alcohol based hydraulic fracturing fluids useful for treating oil and gas wells are disclosed. The fluids are compatible with carbon dioxide, and comprise an alcohol, a polymer, a crosslinking agent, and a breaker. Hydroxypropyl guar with a molar substitution of about 1.2 to about 2.2 is identified as a presently preferred polymer.

Abstract: A well treatment fluid composition that comprises a carrier fluid and an amphoteric surfactant, and optionally a viscosifying agent and proppant, is well suited for use in fracturing coal beds to stimulate methane production. The composition preferably is a foam that comprises a gas such as nitrogen or air. Preferably, the surfactant has the formula R—NH2—(CH2)n—C(O)OX wherein R is a saturated or unsaturated alkyl group having from 6-20 carbon atoms, n is from 2-6, and X is hydrogen or a salt forming cation.

Abstract: The invention provides a method and fluid for drilling or servicing a well in a subterranean formation containing lost circulation zones or depleted, low pressure reservoirs. The fluid comprises an aqueous liquid having dispersed therein a polymer which increases the low shear rate viscosity of the fluid to the extent that the thixotropic index of the fluid is at least about 10 and a surfactant, and wherein the fluid contains less than about 15% by volume of aphrons preferably generated by the turbulence and pressure drop as the fluid exits the drill bit in the vicinity of the formation. The method of drilling a wellbore in a subterranean formation comprises continuously circulating, while drilling, such a drilling fluid.

Abstract: This invention provides a water-free oil based fluid polymer suspension composition for use as a rheology modifier and fluid loss reducer in oil or gas well servicing fluids. It has been found that by using white medicinal oil as a carrier, high solids content and environmental friendly anhydrous fluidized polymer suspensions of xanthan gum, cellulose ethers, guar gum and derivatives thereof can be prepared. More specifically, in one aspect, an oil-based fluid polymer suspension (FPS) composition for use in oil or gas well servicing fluids is preferred containing: a) a hydrophilic polymer, b) an organophilic clay, c) a stabilizer, and d) a white medicinal oil having selected properties.

Abstract: The invention concerns a dispersible and fast hydrating biopolymer in dry form, characterized in that at least 75 wt. % of said biopolymer particles have a diameter ranging between 60 and 250 microns and a mean diameter (d50) ranging between 100 and 200 microns. The invention also concerns the use of such a biopolymer as thickening or viscosity, emulsifying and/or stabilizing agent in industrial, food, cosmetic and pharmaceutical formulations.

Abstract: A drilling fluid comprising a pyruvate-free xanthan, which may be an acetate-free pyruvate-free xanthan, and a high density calcium-based brine. Preferably the pyruvate-free xanthan is a genetically prepared pyruvate-free xanthan. A process for recovering crude oil from an oil-bearing subterranean formation by drilling the formation and using a drilling fluid comprising a pyruvate-free gum and a high density calcium-based brine.

Abstract: The invention includes a composition of matter for increasing the viscosity of an aqueous fluid and for recovering oil from a subterranean formation. It also includes methods for making and using the composition.

Abstract: This invention relates to a wellbore treatment fluid and a method of enhancing wellbore treatment fluids to increase efficiency and productivity of wells. More specifically this invention provides methods for enhancing the thermal stability of wellbore treatment fluids such as drill-in, completion, work-over, packer, well treating, testing, spacer, or hole abandonment fluids. The methods include providing a wellbore treatment fluid that includes a polyol selected from glycerol, glycols and polyglycols as well as a polysaccharide viscosifier. The fluid prepared for use in this invention find particularly advantageous use as a completion fluid and as a fluid loss pill. However, the fluid can include a wide variety of additional agents to modify the physical and chemical properties of the wellbore treatment fluid.

Abstract: A new stable liquid suspension containing non-soluble particles dispersed in a non-aqueous liquid medium having a concentration of a suspension aid and a method of making and use thereof.

Abstract: A process and composition are provided for permeability reduction in a hydrocarbon-bearing formation to improve hydrocarbon recovery therefrom. A moderately epichlorohydrin cross-linked, non-hydroxylpropylated starch is derived from high amylopectin waxy maize starch for use in drilling, workover and completion fluids. The starch is combined with xanthan gum and used in solutions of fresh water, non-saturated brine or saturated brine containing sized salt particles, typically sodium chloride, of various sizes, or sized calcium carbonate, or a combination of sized salt and sized calcium carbonate.

Abstract: The present invention comprises a stable hydrocolloid welan gum in which a hydrocolloid, preferably welan gum, is uniformly dispersed in a superplasticizer such as sulfonated naphthalene, sulfonated melamine, modified lignosulfate, their derivatives and mixtures thereof. This is then dispersed in a rheological control agent which is a microbially-produced cellulose fiber composition. The composition is rapidly hydratable and useful as a stabilizing additive in many cement and drilling fluid applications, insulation fluids and de-icer compositions.

Abstract: A process and composition are provided for permeability reduction in a hydrocarbon-bearing formation to improve hydrocarbon recovery therefrom. A moderately epichlorohydrin cross-linked, non-hydroxylpropylated starch is derived from high amylopectin waxy maize starch for use in drilling, workover and completion fluids. The starch is combined with xanthan gum and used in solutions of fresh water, non-saturated brine or saturated brine containing sized salt particles, typically sodium chloride, of various sizes, or sized calcium carbonate, or a combination of sized salt and sized calcium carbonate.

Abstract: The invention provides water base well drilling and servicing fluids containing a biopolymer viscosifier and a water soluble polyalkylene glycol shale stabilizing additive therein having enhanced thermal stability, as indicated by the low shear rate viscosity at 0.06 sec.sup.-1, the enhanced thermal stability being provided by an amorphous silica viscosifier therein.A method of enhancing the thermal stability of aqueous base well drilling and servicing fluids containing a biopolymer viscosifier and a water soluble polyalkylene glycol shale stabilizing additive therein is disclosed which comprises adding to the fluid an amorphous silica viscosifier.

Abstract: The present invention provides oil based compositions and methods of using the compositions for sealing subterranean zones. The compositions are basically comprised of oil, a hydratable polymer, an organophillic clay and a water-swellable clay.

Abstract: Disclosed are oil-in-water emulsions containing an aqueous polysaccharide-containing continuous phase, an emulsified oleaginous liquid, and an oligosaccharide mixture composed of sugar units selected from the group consisting of arabinose, mannose, galactose, glucose, xylose, and mixtures thereof, and which consists primarily of pentosans and hexosans containing from one to ten sugar units. The emulsions preferably also contain an alkaline earth metal oxide or hydroxide, preferably lime. The emulsions may also contain aphrons. Also disclosed is a method of increasing the low shear rate viscosity of aqueous polysaccharide-containing fluids which comprise incorporating into the fluids an oligosaccharide mixture, an oleaginous liquid, and optionally, an alkaline earth metal oxide or hydroxide.

Abstract: The invention, in one embodiment, is a novel fracturing fluid composition comprising an aqueous metal hydrated galactomannan gum, buffered to a pH of from about 9 to about 11. In another embodiment, a method of fracturing a formation is disclosed, the method being characterized by the use of the compositions mentioned.

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: Disclosed is a method of increasing the thermal stability or decreasing the fluid loss of aqueous polysaccharide-containing fluids which comprises incorporating into the fluids an oligosaccharide mixture composed of arabinose, mannose, galactose, glucose, and xylose sugar units, the oligosaccharide mixture consisting of the water soluble portion of thermally hydrolyzed lignocellulose and consisting primarily of pentosans and hexosans containing from one to four combined sugar units.Preferred fluids contain a biopolymer which increases the low shear rate viscosity of the fluids. Fluids which contain polysaccharides which impart other desirable characteristics to the fluids, such as increased viscosity at higher shear rates, fluid loss control, and the like, also exhibit increased thermal stability upon incorporating the oligosaccharide mixture therein.

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 for the treatment of oil wells having a high content of "acid gases", comprises circulating through or pumping into the well a slurry comprising a water-soluble, solid salt and a saline solution, which slurry does not react with the "acid gases" and which has a density of more than 13 and preferably of at least 14 lb/gal.

Abstract: A well completion spacer fluid is provided which is particularly suitable for separating a cement slurry from drilling fluid in primary cementing operations. The well completion spacer fluid is also useful for separating other potentially incompatible fluids in the wellbore, such as, separating drilling fluid from a completion brine. The spacer fluid basically comprises water, a hydrous magnesium silicate clay, silica and organic polymer(s).

Abstract: The present invention provides compositions useful for viscosifying aqueous fluids, methods for making them and methods for using them. In one aspect of the invention, inventive compositions comprise a prehydrating alcohol having at least two hydroxyl groups and having a molecular weight of from about 60 to about 600; an inorganic salt; and a polymer. In a preferred aspect of the invention, the viscosifier composition additionally comprises a solvent having a molecular weight of from about 75 to about 1000. According to another aspect of the invention, inventive compositions comprise a prehydrating alcohol; an inorganic salt; and a polymer; and the composition is essentially free from water. Inventive compositions find advantageous use in viscosifying fluids utilized in subterranean drilling activities such as, for example, drilling, drill-in, completion, hydraulic fracturing, work-over, packer, well treating, testing, spacer, or hole abandonment fluids.

Abstract: The invention provides alkaline water base well drilling and servicing fluids which deposit an easily degradable and removable filter cake on the sides of a borehole during well drilling and servicing operations. The fluids contain one or more polysaccharide polymers, sized bridging particles, and a peroxide selected from the group consisting of alkaline earth metal peroxides, zinc peroxide, and mixtures thereof. The fluids deposit a filter cake containing the peroxide.

Abstract: Improved high viscosity well treating fluids for use at temperatures above about 200.degree. F., gel breaking additives for the treating fluids and methods of using the treating fluids are provided by the present invention. The high viscosity well treating fluids are basically comprised of an aqueous liquid, a polysaccharide gelling agent to increase the viscosity of the aqueous liquid and a gel breaker comprised of a bromate ion releasing compound to reduce the viscosity of the aqueous liquid after a desired period of time.

Abstract: Disclosed are low solids, high density fluids useful as drilling, workover, and completion fluids and the like in oil and gas well operations. The fluids comprise a brine having dissolved therein a zinc salt such as zinc bromide, and optionally one or more additional water soluble salts, a viscosifier which is a high surface area silica, a biopolymer viscosifier, a fluid loss control additive which is preferably a starch derivative, zinc carbonate, and, optionally, an alkaline buffer, a polar additive, and a bridging agent.It has been found that zinc carbonate will increase the low shear rate viscosity of fluids containing a zinc salt dissolved therein. Additionally, the combination of zinc carbonate and zinc oxide as the alkaline buffer provides fluids having increased thermal stability as indicated by the low shear rate viscosity of the fluids.

Abstract: The invention involves biopolymer/oil suspension compositions for the oil service industry, most particularly drilling and completion fluids, which provide such fluids a variety of desirable properties. Biopolymers include water soluble polymers and water swellable polymers. Such biopolymer/oil suspension compositions are essentially mixtures of biopolymers such as cellulosics in an oil medium with a specific anti-settling additive. The invention is particularly directed to providing enhanced anti-settling properties to such biopolymer/oil compositions; that is, the ability of the biopolymer/oil composition to retain the biopolymers in suspension prior to the composition being introduced into drilling and completion fluids. The invention in one embodiment is described as a liquid biopolymer-in-oil additive compositions for use in aqueous-based completion fluids, containing an agent comprising: a) one or more polyamides, and b) hydrogenated caster oils including castorwax.

Abstract: Polymer enhanced foam fluid is utilized for completion, workover, and kill operations in wells penetrating subterranean formations. The foam is formed by appropriately adding a gas to an aqueous solution of a substantially noncrosslinked water soluble polymer and a surfactant. The solution and the foam are substantially free of crosslinking agents. The foam may be generated at the surface or in a wellbore.

Abstract: The crosslinking of galactomannan gum fracturing fluids by borate ion is delayed for high-temperature applications by encapsulating the boron with a polymer coating. The crosslink-delay time is further adjusted by varying the concentration of an organic polyol. The polyol also acts as a stabilizer for the crosslinked fluid at elevated temperatures. Low pumping friction pressures are achieved by the delay in the crosslinking with the boron available at high temperatures to add high-temperature stability to the fracturing fluid at temperatures ranging up to about 350.degree. F.

Abstract: Base composition for water-based drilling muds allowing the number and the amount of the other constituents of the mud to be restricted. In addition to the base solvent, fresh water, sea water or salt water, the said base composition comprises scleroglucan as viscosity agent, the mycelium which produced it and bentonite or an equivalent in limited amount.

Abstract: A non-acetylated but otherwise unmodified xanthan heteropolysaccharide polymer plus guar gum, is employed to impart viscosity to an aqueous particle transport fluid (such as a drilling fluid, a fracturing fluid, or a filter structure emplacement fluid) sufficient to suspend mineral particles. A cross linking agent can also be employed to decrease the amounts of xanthan heteropolysaccharide polymer and guar gum which are needed for particle suspension.