Abstract: A microemulsion delivery system containing a well treatment agent in a water-in-oil microemulsion may be used for well remediation as well as in other treatment operations including stimulation, acidizing, and drilling. In addition, the water-in-oil microemulsion delivery system may be used to clean surface equipment and downhole equipment.

Abstract: A well treatment fluid contains a viscoelastic surfactant and a viscosification activator. The viscosification activator enhances the viscosity of the well treatment fluid in contrast to a treatment fluid that does not contain a viscosification activator.

Abstract: A well servicing fluid is formulated by combining ingredients comprising: an aqueous based fluid comprising sulfate ions at a concentration greater than 50 mg/l; a chelating agent; and an acid in an amount sufficient to result in the well servicing fluid having a pH of 4.5 or less. A method of servicing a well is also disclosed.

Abstract: A well servicing fluid is disclosed. The well servicing fluid is formulated by combining ingredients comprising: an aqueous based fluid comprising sulfate ions at a concentration greater than 50 mg/l; a chelating agent; and an acid in an amount sufficient to result in the well servicing fluid having a pH of 4.5 or less. A method of servicing a well is also disclosed.

Abstract: A microemulsion delivery system containing a well treatment agent in a water-in-oil microemulsion may be used for well remediation as well as in other treatment operations including stimulation, acidizing, and drilling. In addition, the water-in-oil microemulsion delivery system may be used to clean surface equipment and downhole equipment.

Abstract: Brine-based well treatment compositions containing alkali nitrate exhibit greater thermal stability when used in deep wells than substantially similar brine-based well treatment compositions which do not contain an alkali nitrate. The brine is thickened with a water-soluble crosslinkable polymer and crosslinking agent. The enhanced thermal stability of the well treatment compositions allows use of the fluids at elevated temperatures, for instance as high as 400° F.

Abstract: Brine-based well treatment compositions containing alkali nitrate exhibit greater thermal stability when used in deep wells than substantially similar brine-based well treatment compositions which do not contain an alkali nitrate. The brine is thickened with a water-soluble crosslinkable polymer and crosslinking agent. The enhanced thermal stability of the well treatment compositions allows use of the fluids at elevated temperatures, for instance as high as 400° F.

Abstract: A method of acidizing a subterranean formation with a diverting agent composed of a gelled or thickened viscoelastic foam or fluid generated from (i.) an amidoamine oxide gelling agent and (ii.) an acid or foam, water and/or brine. The gelled or thickened foam or fluid may be generated in-situ or introduced directly into the formation by mixing of the amidoamine oxide gelling agent and acid or foam, water and/or brine. As the acid spends, the acidizing fluid thickens. When the acid is further spent, the fluid viscosity declines eventually returning to a low viscosity state, allowing for easy cleanup. The process allows for selective acidizing of less permeable zones of the formation and more uniform stimulation of the hydrocarbon bearing formation.

Abstract: A well treatment fluid contains a viscoelastic surfactant and a viscosification activator. The viscosification activator enhances the viscosity of the well treatment fluid in contrast to a treatment fluid that does not contain a viscosification activator.

Abstract: A method of treating a well consists of introducing into the wellbore a biodegradable fluid system containing a fatty acid ester, such as methyl soyate. The fluid system may further contain a lactic acid ester, such as ethyl lactate, and/or a nonionic surfactant. The fluid system may be used in displacement, well remediation and stimulation as well as additional, alternative applications such as the cleaning of surface and/or downhole equipment.

Abstract: A method of acidizing a subterranean formation with a diverting agent composed of a gelled or thickened viscoelastic foam or fluid generated from (i.) an amidoamine oxide gelling agent and (ii.) an acid or foam, water and/or brine. The gelled or thickened foam or fluid may be generated in-situ or introduced directly into the formation by mixing of the amidoamine oxide gelling agent and acid or foam, water and/or brine. As the acid spends, the acidizing fluid thickens. When the acid is further spent, the fluid viscosity declines eventually returning to a low viscosity state, allowing for easy cleanup. The process allows for selective acidizing of less permeable zones of the formation and more uniform stimulation of the hydrocarbon bearing formation.

Abstract: A method of acidizing a subterranean formation with a diverting agent composed of a gelled or thickened viscoelastic foam or fluid generated from (i.) an amidoamine oxide gelling agent and (ii.) an acid or foam, water and/or brine. The gelled or thickened foam or fluid may be generated in-situ or introduced directly into the formation by mixing of the amidoamine oxide gelling agent and acid or foam, water and/or brine. As the acid spends, the acidizing fluid thickens. When the acid is further spent, the fluid viscosity declines eventually returning to a low viscosity state, allowing for easy cleanup. The process allows for selective acidizing of less permeable zones of the formation and more uniform stimulation of the hydrocarbon bearing formation.

Abstract: A method of treating a well consists of introducing into the wellbore a biodegradable fluid system containing a blend of lactic acid ester, such as ethyl lactate, and a fatty acid ester, such as methyl soyate. The fluid system may be further in the form of a microemulsion that is formed by combining a blend with one or more emulsifiers, an alcohol, and water. The fluid system may be used in displacement, well remediation and stimulation as well as additional, alternative applications such as the cleaning of surface and/or downhole equipment.

Abstract: The invention, in one embodiment, relates to a fluid loss control additive or composition comprising a granular starch composition and fine particulate mica, in specified proportions. The invention further comprises a fracturing fluid containing a starch composition and mica, in a specified ratio. In yet a third embodiment, the invention comprises a method of fracturing a subterranean formation penetrated by a borehole, comprising injecting into the borehole and into contact with the formation, at a rate and pressure sufficient to fracture the formation, a fracturing fluid containing starch and mica, in specified ratios, and in an amount sufficient to provide fluid loss control.

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: A high internal phase ratio water-in-oil emulsion containing an emulsifier comprising a block or graft copolymer the general formula (A-COO).sub.mB or a reaction product of a polyalk(en)yl succinic anhydride and a polar compound having at least one hydroxyl or amino group demonstrates surprisingly low pumping friction pressure losses, high temperature stability and excellent proppant carrying capacity for use as a fracturing fluid in the hydraulic fracturing of subterranean formation.

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: A tertiary amine hydrochloride/persulfate breaker system as disclosed which effects complete breaks of polysaacharide-based gels or fluids in a the ambient temperature range without interfering with delayed crosslink mechanism in the fracturing fluid. The use of tertiary amine hydrochloride avoids an immediate shift in pH which would counteract means employed to effect a delayed crosslink mechanism.

Abstract: An improved process for flocculating and clarifying colloidal coal slurries comprises contacting a coal liquor with a water-soluble, low molecular weight polymer with high anionic character; an inorganic coflocculant; and a water-soluble high molecular weight polymer with low anionic character. The low molecular weight polymer contains at least 50 mole percent nonionic monomer. The process allows coal liquor clarification to be performed using low total polymer dosages.