Abstract: Compositions for increasing the thermal and pressure stability of well fluids viscosified using viscoelastic surfactants, the compositions including an effective amount of an oligomeric or polymeric compound that has a thermally stable backbone structure and at least one pendent viscoelastic surfactant functional group. Preferred compositions for increasing the stability of well fluids viscosified using monomeric viscoelastic surfactants include an effective amount of an oligomeric or polymeric compound that has a thermally stable backbone structure and a multiplicity of pendent viscoelastic surfactant functional groups attached to said backbone structure through relatively long hydrocarbon chains, 1 to 18 carbons in length.

Abstract: A method of controlling and delaying the inversion of a drilling fluid and the wettability of a filtercake by using a delayed phase changing agent. The filtercake is preferably formed while drilling a subterranean formation using a drilling fluid includes: an oleaginous fluid; a non-oleaginous fluid; an amine surfactant having the structure: wherein R is a C12–C22 aliphatic hydrocarbon; R? is an independently selectable from hydrogen or C1 to C3 alkyl; A is NH or O, and 1?x+y?3. In the method, the filter cake is exposed to a delayed phase changing agent selected from the group consisting of aliphatic amine acids, salts of aliphatic amine acids and combinations thereof. In one preferred illustrative embodiment, the delayed phase changing agent is delivered in the form of a pill, the pill including a carrier fluid, a viscosifier and the delayed phase changing agent.

Abstract: A process to substantially reduce fluid loss in which an appropriate amount of a non-flowing gel of sufficient strength is emplaced to substantially eliminate or reduce loss of the drilling fluid. The gel composition of the process includes: (1) a non-cellulose containing copolymer having vinyl phosphonate co-monomer units which may be incorporated into the polymer by copolymerization with the other co-monomer(s) comprising the polymer or by grafting upon an already existing polymer or co-polymer, (2) a crosslinking agent active upon the phosphonate groups, (3) a crosslinking initiator comprising a Bronsted Lowry base or Lewis base and (4) an aqueous solvent.

Abstract: Compositions for increasing the thermal and pressure stability of well fluids viscosified using viscoelastic surfactants, the compositions including an effective amount of an oligomeric or polymeric compound that has a thermally stable backbone structure and at least one pendent viscoelastic surfactant functional group. Preferred compositions for increasing the stability of well fluids viscosified using monomeric viscoelastic surfactants include an effective amount of an oligomeric or polymeric compound that has a thermally stable backbone structure and a multiplicity of pendent viscoelastic surfactant functional groups attached to said backbone structure through relatively long hydrocarbon chains, 1 to 18 carbons in length.

Abstract: An annular fluid or packer fluid, and methods of making the same, that includes a water-miscible solvent, a viscosifying additive, a crosslinking agent, a crosslinking inhibitor having the facility to inhibit crosslinking between the viscosifying additive and the crosslinking agent, and an initiating agent having the facility to overcome an action of the crosslinking inhibitor and to initiate crosslinking between the viscosifying additive and the crosslinking agent, is shown and described. The fluid has a thermal conductivity of no more than about 0.25 btu/(hr·ft·° F.) and a potential to substantially increase its viscosity upon sitting for a selected period of time.

Abstract: A method of controlling and delaying the inversion of a drilling fluid and the wettability of a filtercake by using a delayed phase changing agent.

Abstract: Compositions for increasing the thermal and pressure stability of well fluids viscosified using viscoelastic surfactants, the compositions including an effective amount of an oligomeric or polymeric compound that has a thermally stable backbone structure and at least one pendent viscoelastic surfactant functional group. Preferred compositions for increasing the stability of well fluids viscosified using monomeric viscoelastic surfactants include an effective amount of an oligomeric or polymeric compound that has a thermally stable backbone structure and a multiplicity of pendent viscoelastic surfactant functional groups attached to said backbone structure through relatively long hydrocarbon chains, 1 to 18 carbons in length.