Abstract: A method of treating a subterranean formation penetrated by a wellbore involves introducing an acid treatment fluid through the wellbore into the formation. The treatment fluid is formed from a zwitterionic viscoelastic surfactant, an acid in an amount to provide the treatment fluid with an initial pH of ?0 and a rheology enhancer. The treatment fluid has a high viscosity at the initial pH and a lower viscosity when the pH of the treatment fluid is raised to an intermediate pH of from greater than 0 to about 5.

Abstract: Example methods and apparatus to perform stress testing of geological formations are disclosed. A disclosed example downhole stress test tool for pressure testing a geological formation comprises first and second packers selectively inflatable to form an annular region around the tool, a container configured to store a fracturing fluid, wherein the fracturing fluid is different than a formation fluid and a drilling fluid, a pump configured to pump the fracturing fluid into the first and second packers to inflate the first and second packers and to pump the fracturing fluid into the annular region to induce a fracture of the geological formation, and a sensor configured to detect a pressure of the fracturing fluid pumped into the annular region corresponding to the fracture of the geological formation.

Abstract: A method of treating a subterranean formation penetrated by a wellbore involves introducing an acid treatment fluid through the wellbore into the formation. The treatment fluid is formed from a zwitterionic viscoelastic surfactant, an acid in an amount to provide the treatment fluid with an initial pH of ?0 and a rheology enhancer. The treatment fluid has a high viscosity at the initial pH and a lower viscosity when the pH of the treatment fluid is raised to an intermediate pH of from greater than 0 to about 5.

Abstract: Example methods and apparatus to perform stress testing of geological formations are disclosed. A disclosed example downhole stress test tool for pressure testing a geological formation comprises first and second packers selectively inflatable to form an annular region around the tool, a container configured to store a fracturing fluid, wherein the fracturing fluid is different than a formation fluid and a drilling fluid, a pump configured to pump the fracturing fluid into the first and second packers to inflate the first and second packers and to pump the fracturing fluid into the annular region to induce a fracture of the geological formation, and a sensor configured to detect a pressure of the fracturing fluid pumped into the annular region corresponding to the fracture of the geological formation.

Abstract: An oilfield treatment method is given that uses fluids that contain surfactants used as foamers and/or viscosifiers such that the fluids pass the Alberta Energy and Utilities Board Directive 27 requirements for low toxicity to certain bioluminescent bacteria. Such fluids may be used in oilfield treatments, for example drilling and stimulation, near fresh water aquifers. The surfactants are certain non-ionic surfactants that are not aromatic, or certain amphoteric surfactants (that can be neutral), or certain zwitterionic surfactants, (in which both positive and negative charges are present in a single molecule so that the whole molecule is neutral).

Abstract: A method of forming a gelled organic-based fluid is disclosed. The method comprises combining an organic solvent, a viscoelastic surfactant, and a metal carboxylate crosslinker; and forming the gelled organic-based fluid. In a further aspect, the method is used to treat a subterranean formation of a well, for example for a stimulation job as fracturing or the like.

Abstract: An oilfield treatment method is given that uses fluids that contain surfactants used as foamers and/or viscosifiers such that the fluids pass the Alberta Energy and Utilities Board Directive 27 requirements for low toxicity to certain bioluminescent bacteria. Such fluids may be used in oilfield treatments, for example drilling and stimulation, near fresh water aquifers. The surfactants are certain non-ionic surfactants that are not aromatic, or certain amphoteric surfactants (that can be neutral), or certain zwitterionic surfactants, (in which both positive and negative charges are present in a single molecule so that the whole molecule is neutral).

Abstract: A fluid-loss pill that includes a brine solution and an effective amount of a viscoelastic surfactant is disclosed. The viscoelastic surfactant preferably includes at least one compound selected from the family of compounds described by where R1, R2, R3, R4 and R5 are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R1 contains 16–26 carbon atoms, R2 contains 2–10 carbon atoms, R3, R4 and R5 contains 1–6 carbon atoms. Methods of treating a well that include injecting fluid-loss pill into a well to control lost-circulation or to kill a well.

Abstract: A fluid-loss pill that includes a brine solution and an effective amount of a viscoelastic surfactant is disclosed. The viscoelastic surfactant preferably includes at least one compound selected from the family of compounds described by where R1, R2, R3, R4 and R5 are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R1 contains 16-26 carbon atoms, R2 contains 2-10 carbon atoms, R3, R4 and R5 contains 1-6 carbon atoms. Methods of treating a well that include injecting fluid-loss pill into a well to control lost-circulation or to kill a well.

Abstract: A fluid-loss pill that includes a brine solution and an effective amount of a viscoelastic surfactant is disclosed.