Abstract: A water-free slurry may include a non-aqueous carrier fluid; a suspension agent including a mineral clay mixture; a crosslinking agent; and a hydratable polymer. A method of treating a subterranean formation may include injecting a water-free slurry into a wellbore penetrating the subterranean formation, the water-free slurry including: a non-aqueous carrier fluid; a suspension agent comprising a mineral clay mixture; a crosslinking agent; and a hydratable polymer.

Abstract: A water-free slurry may include a non-aqueous carrier fluid; a suspension agent including a mineral clay mixture; a crosslinking agent; and a hydratable polymer. A method of treating a subterranean formation may include injecting a water-free slurry into a wellbore penetrating the subterranean formation, the water-free slurry including: a non-aqueous carrier fluid; a suspension agent comprising a mineral clay mixture; a crosslinking agent; and a hydratable polymer.

Abstract: The invention provides a method made of steps of injecting into a wellbore, a composition comprising a solvent, a surfactant, a foaming gas, a foam enhancer, a crosslinkable polymer, and a crosslinking agent capable of crosslinking the polymer, wherein the foam enhancer increases the foam half-life of the gel composition compared to the gel composition without the foam enhancer; and allowing viscosity of the composition to increase and form a gel.

Abstract: A composition and method for performing a viscosity reducing treatment of a subterranean formation. The composition includes a sulfobetaine surfactant. The composition and method can employ viscosity reduction of heavy crude oil in a subterranean formation.

Abstract: Fluid compositions comprising water, an acid or an acid source, a chelating agent and a relative permeability modifier have utility in the context of matrix acidizing of oil bearing sandstone formations. Acidizing treatments with these compositions may improve the formation permeability to oil with respect to the permeability to water. The relative permeability modifier is a cationic polyacrylamide.

Abstract: The invention provides a method made of steps of injecting into a wellbore, a composition comprising a solvent, a surfactant, a foaming gas, a foam enhancer, a crosslinkable polymer, and a crosslinking agent capable of crosslinking the polymer, wherein the foam enhancer increases the foam half-life of the gel composition compared to the gel composition without the foam enhancer; and allowing viscosity of the composition to increase and form a gel.

Abstract: The invention discloses a method of for changing the water permeability of a subterranean formation of a well, the method comprising: providing a fluid comprising a liquid carrier and a viscoelastic surfactant; introducing the fluid into the well; and contacting the fluid and the subterranean formation wherein the action of the liquid carrier and the viscoelastic surfactant is able to change the water permeability of the subterranean formation. The fluid may further comprise methanol, or a salt which can be embodied within the carrier fluid. Advantageously, no further RPM polymer is used. In a first aspect the method is used for reducing the amount of water produced, in as second aspect for improving the oil recovery.

Abstract: A fluid containing a viscous hyposaline aqueous solution of first and second cationic polymers that include quatemized ammonium groups, wherein the first cationic polymer includes a hydrophilic base polymer structure and the second cationic polymer includes a lipophilic base polymer Also disclosed is a method of introducing the viscous fluid into an initial first interval of a subterranean formation, and diverting with the viscous fluid a treating fluid from the initial first interval to an initial second interval.

Abstract: The invention provides a method made of steps of injecting into a wellbore, a composition comprising a solvent, a surfactant, a foaming gas, a foam enhancer, a crosslinkable polymer, and a crosslinking agent capable of crosslinking the polymer, wherein the foam enhancer increases the foam half-life of the gel composition compared to the gel composition without the foam enhancer; and allowing viscosity of the composition to increase and form a gel.

Abstract: Embodiments of the invention relate to a method for treating a subterranean formation, comprising forming a fluid comprising polyacrylamide and a biopolymer and introducing the fluid to a subterranean formation wherein the polyacrylamide and biopolymer are selected to form the fluid with a longer foam half life and a higher viscosity than if only one polymer were selected. Embodiments of the invention relate to a method for treating a subterranean formation, comprising forming a fluid comprising polyacrylamide and a biopolymer and introducing the fluid to a subterranean formation wherein the polyacrylamide does not alter biopolymer crosslinking.

Abstract: The invention discloses a well treatment composition for use in a subterranean formation comprising: a carrier fluid; and a viscoelastic surfactant being present in a concentration of less than about 1.5% by weight. Optionally, the fluid comprises a crosslinked polymer in a thickening amount in the carrier fluid. The invention also discloses a method to increase the viscosity of a fluid, the method comprising: providing a fluid comprising a thickening amount of a crosslinked polymer; adding a viscoelastic surfactant at a given concentration to the fluid; taking the fluid to a given temperature; defining a viscosity profile of the fluid depending of the concentration and the temperature; comparing said viscosity profile to a viscosity profile of the crosslinked polymer fluid alone; and defining an optimum concentration of the viscoelastic surfactant for each temperature.

Abstract: The invention discloses a well treatment composition for use in a subterranean formation comprising: a carrier fluid; and a viscoelastic surfactant being present in a concentration of less than about 1.5% by weight. Optionally, the fluid comprises a crosslinked polymer in a thickening amount in the carrier fluid. The invention also discloses a method to increase the viscosity of a fluid, the method comprising: providing a fluid comprising a thickening amount of a crosslinked polymer; adding a viscoelastic surfactant at a given concentration to the fluid; taking the fluid to a given temperature; defining a viscosity profile of the fluid depending of the concentration and the temperature; comparing said viscosity profile to a viscosity profile of the crosslinked polymer fluid alone; and defining an optimum concentration of the viscoelastic surfactant for each temperature.

Abstract: A fluid comprising a viscous hyposaline aqueous solution of first and second cationic polymers comprising quaternized ammonium groups, wherein the first cationic polymer comprises a hydrophilic base polymer structure and the second cationic polymer comprises a lipophilic base polymer structure, and a method comprising introducing the viscous fluid into an initial first interval of a subterranean formation, and diverting with the viscous fluid a treating fluid from the initial first interval to an initial second interval. The fluid and method are useful to modify a hydrocarbon reservoir formation for improved relative permeability of oil with respect to water to enhance hydrocarbon production from the reservoir.

Abstract: The invention discloses a well treatment composition for use in a subterranean formation comprising: a carrier fluid; and a viscoelastic surfactant being present in a concentration of less than about 1.5% by weight. Optionally, the fluid comprises a crosslinked polymer in a thickening amount in the carrier fluid. The invention also discloses a method to increase the viscosity of a fluid, the method comprising: providing a fluid comprising a thickening amount of a crosslinked polymer; adding a viscoelastic surfactant at a given concentration to the fluid; taking the fluid to a given temperature; defining a viscosity profile of the fluid depending of the concentration and the temperature; comparing said viscosity profile to a viscosity profile of the crosslinked polymer fluid alone; and defining an optimum concentration of the viscoelastic surfactant for each temperature.

Abstract: The invention discloses a method of for changing the water permeability of a subterranean formation of a well, the method comprising: providing a fluid comprising a liquid carrier and a viscoelastic surfactant; introducing the fluid into the well; and contacting the fluid and the subterranean formation wherein the action of the liquid carrier and the viscoelastic surfactant is able to change the water permeability of the subterranean formation. The fluid may further comprise methanol, or a salt which can be embodied within the carrier fluid. Advantageously, no further RPM polymer is used. In a first aspect the method is used for reducing the amount of water produced, in as second aspect for improving the oil recovery.

Abstract: A method for treating a subterranean formation penetrated by a wellbore utilizes forming at least one of a treatment fluid A and a treatment fluid B. The treatment fluid A comprises an aqueous carrier fluid, a first relative permeability modifier (RPM) polymer, a water-soluble viscosifying polymer and a crosslinking agent capable of crosslinking the viscosifying polymer at a pH of from about 3 to about 5. The treatment fluid B comprises a fresh-water carrier fluid and a second relative permeability modifier (RPM), and optionally an amount of fibers. At least one of the treatment fluids A and B is introduced into the formation through the wellbore.

Abstract: A method of treating a subterranean formation with a retarded self-diverting fluid system. The method includes contacting the formation with a mixture of acid, chelating agent, and betaine surfactant in which the betaine surfactant is mixed with an aqueous solution of the chelating agent in which the pH has been adjusted to a pH of below about 3.0, but above the pH at which the free acid of the chelating agent precipitates, and the resulting fluid system is utilized for both acid fracturing and matrix stimulation, as well as workover procedures such as scale and filter cake removal, especially in high temperature formations.

Abstract: Disclosed are acid fracturing methods for subterranean siliceous formations employing a viscous dissolving fluid to create a permeable conduit that bypasses the near wellbore damage. The viscous dissolving fluids used according to the invention are acid-fracturing treatment fluids containing a dissolving agent viscosified with a material such as a viscoelastic surfactant, and the fluid is injected into a sandstone formation at a pressure sufficient to create a hydraulic fracture. Also, the viscous dissolving fluid leaks off into the faces of the fracture thus “stimulating” the formation. Hence when the hydraulic fracture has closed there is a part of the formation that has been effectively stimulated, creating a pathway for fluids to preferentially flow to the wellbore. The formation may then be flowed back to produce a substantial volume of the treatment fluid.

Abstract: Disclosed are acid fracturing methods for subterranean siliceous formations employing a viscous dissolving fluid to create a permeable conduit that bypasses the near wellbore damage. The viscous dissolving fluids used according to the invention are acid-fracturing treatment fluids containing a dissolving agent viscosified with a material such as a viscoelastic surfactant, and the fluid is injected into a sandstone formation at a pressure sufficient to create a hydraulic fracture. Also, the viscous dissolving fluid leaks off into the faces of the fracture thus “stimulating” the formation. Hence when the hydraulic fracture has closed there is a part of the formation that has been effectively stimulated, creating a pathway for fluids to preferentially flow to the wellbore. The formation may then be flowed back to produce a substantial volume of the treatment fluid.

Abstract: Propped fractures in formations from which fluids are produced are described that have wormholes extending out into the formations from the faces of the fractures at locations distant from boreholes. Methods are given for creating such propped fractures having wormholes in which either a closed propped fracture is formed and then the wormholes are formed, or the entire fracture and channel system is formed before the closure occurs.