Abstract: An oil or gas well penetrating a subterranean formation, such as a carbonate formation, is treated with a well treatment fluid which contains an organic ester. The fluid may be an oil-in-water emulsion of the organic ester and an emulsifier or a homogeneous solution of organic ester and a water/mutual solvent solution. Acid is produced in-situ by hydrolysis of the organic ester.

Abstract: The present invention is directed to a method for enhancing the recovery of oil from a subterranean reservoir which method employs an alkylxylene sulfonate that contains a high percentage of the 4-alkyl-1,2-dimethyl benzene isomer and a high percentage of alkyl group attachment to the xylene ring at positions higher than the 2-position on the alkyl carbon chain in an aqueous media, since it has surprisingly been discovered that the high percentage of the 4-alkyl-1,2-dimethyl benzene isomer and the high percentage alkyl group attachment to the xylene moiety at positions higher than the 2-position along the alkyl carbon chain on the alkylxylene sulfonate provides an enhanced oil recovery surfactant having low Interfacial Tension. The method optionally employs co-surfactants.

Abstract: A method for increasing the rate of shear rehealing of fluids made with cationic, zwitterionic, and amphoteric viscoelastic surfactant fluid systems by adding an effective amount of a rheology enhancer package containing, for example a polyethylene glycol-polypropylene glycol block copolymer and a polynaphthalene sulfonate. The rheology enhancer package allows viscoelastic surfactant fluids to be used at lower viscoelastic surfactant concentrations in certain applications, for example certain oilfield treatments, for example fracturing and gravel packing. Preferred surfactants are betaines and quaternary amines.

Abstract: The present invention is directed to alkylxylene sulfonate for enhanced oil recovery processes. The alkylxylene moiety in the alkylxylene sulfonate contains a high percentage of the 4-alkyl-1,2-dimethyl benzene isomer and a high percentage of alkyl group attachment to the xylene ring at positions higher than the 2-position on the alkyl carbon chain. The present invention is also directed to a method for enhancing the recovery of oil from a subterranean reservoir which method employs the alkylxylene sulfonate of the present invention. The alkylxylene sulfonate is employed in an aqueous media. The method optionally employs co-surfactants.

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: Methods in which temperature is used to control the foaming and/or defoaming of foamed treatment fluids comprising an aqueous liquid, an ionic foaming surfactant, and a gas are provided. A method of treating at least a portion of a subterranean formation is provided, the method comprising: providing a treatment fluid having a foam transition temperature, the treatment fluid comprising an aqueous liquid, and an ionic foaming surfactant; foaming the treatment fluid to form a foamed treatment fluid; circulating the foamed treatment fluid in a well bore penetrating the subterranean formation; and defoaming at least a substantial portion of the foamed treatment fluid, the defoaming comprising lowering the temperature of the foamed treatment fluid to about at or below the foam transition temperature.

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: 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: 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: Present invention relates to high brine carrier fluid, said carrier fluid selected from the group consisting of organic acids, organic acid salts, inorganic salts and combination of one or more organic acids or organic acid salts, a co-surfactant and an amount of a zwitterionic surfactant. The invention also relates to methods of treating a subterranean wellbore, including drilling, hydraulic fracturing, gravel placement, scale removing, mud cake removing, using said high brine carrier fluid.

Abstract: Process for recovering and moving refinery tar by the formation of oil in water dispersions of the above tar, the above dispersions having a water content of at least 20% by weight, and the dispersing agent being selected from salts of alkaline metals and ammonium, and relative mixtures, of the condensates of naphthalenesulfonic acid with formaldehyde, which comprises:

Abstract: The corrosion of metal equipment which is cleaned with an inorganic acid is inhibited by treating the equipment with a corrosion inhibitor composition containing at least one quaternary ammonium compound, a sulfur-containing compound and a nonionic surfactant in a solvent.

Abstract: The invention describes a method for decreasing the viscosity of crude oils and residuum utilizing a combination of thermal and acidic treatment. Further, the invention describes a method for making a water-in-oil emulsion, or a solids-stabilized water-in-oil emulsion with a reduced viscosity. The emulsion can be used in enhanced oil recovery methods, including using the emulsion as a drive fluid to displace hydrocarbons in a subterranean formation, and using the emulsion as a barrier fluid for diverting flow of fluids in the formation.

Abstract: An acid corrosion inhibitor composition is provided for petroleum wells and water wells subjected to stimulation with acid solutions. The inhibitor combines cinnamaldehyde and an organo-sulfur compound. The inhibitor provides a reduced rate of corrosion and fewer instances of pitting than inhibitors which include cinnamaldehyde alone. The inhibitor does not suffer from the well-known oil field aldehyde/polyacrylamide crosslinking incompatibility. The enhanced performance by the inhibitor of the present invention is provided by a synergistic action between the cinnamaldehyde and an organo-sulfur compound.

Abstract: A thermally stable well servicing fluid includes a fluid portion in the form of an oil-in-water emulsion; and a surfactant mixture including an anionic surfactant selected from the group consisting of alkali metal salts of alkyl sulphates, alkali metal salts of alkyl sulphonates, and mixtures thereof, and a non-ionic surfactant selected from the group consisting of ethoxylated alkyl phenols, ethoxylated aliphatic alcohols and mixtures thereof, the surfactant mixture containing the anionic surfactant and the non-ionic surfactant at a ratio by weight of between about 70:30 to about 80:20, the fluid being stable at temperatures exceeding 220.degree. F.

Abstract: A well fluid emusion having a water phase and an oil phase of a sulfurized alcohol and a naturally occuring fat, oil or derivatives thereof. Also disclosed is a method of lubricating drilling equipment used in conjunction with the drilling, completion or workover of a subterranean well. The method includes introducing the above emulsified well fluid into the well for circulation through and out of the well, and further includes contacting the surface of the drilling equipment with the emulsified well fluid to provide an interface between the equipment surface and the water phase. Suitable naturally occurring fats and oils may be obtained from the following animal oils and fats: butter, lard, tallow, grease, herring, menhaden, pilchard and sardine; and from the following vegetable oils and fats: castor, coconut, coffee, corn, cottonseed, jojoba, linseed, liticica, olive, palm, palm kernel, peanut, rapeseed, safflower, soya, sunflower, tall and tung.