Abstract: Of the many methods and compositions provided herein, in one embodiment, the invention provides a method comprising: providing an oil-wet well bore surface; providing a surfactant wash treatment fluid that comprises an acid-compatible surfactant, an acid and/or an acid-generating component, and an aqueous fluid; contacting the oil-wet well bore surface with the surfactant wash treatment fluid; allowing the oil-wet well bore surface to become water-wet; and producing fluids from the formation. In another embodiment, the invention provides a surfactant wash treatment fluid for use in a subterranean formation comprising an aqueous fluid, an acid-compatible surfactant, an acid and/or an acid-generating component.

Abstract: An inhibitive water-based polymer mud system and method for using the system in drilling and in stabilizing wellbores is disclosed for use in water sensitive formations as an alternative to oil-based muds. The system comprises a substantially non-ionic low molecular weight polyacrylamide in combination with a substantially non-ionic high molecular weight polyacrylamide, preferably long chain alcohol or an amine or silicate shale inhibitor, and poly anionic cellulose.

Abstract: An inhibitive water-based polymer mud system and method for using the system in drilling and in stabilizing wellbores is disclosed for use in water sensitive formations as an alternative to oil-based muds. The system comprises a substantially non-ionic low molecular weight polyacrylamide in combination with a substantially non-ionic high molecular weight polyacrylamide, preferably long chain alcohol or an amine or silicate shale inhibitor, and poly anionic cellulose.

Abstract: Of the many methods and compositions provided herein, in one embodiment, the invention provides a method comprising: providing an oil-wet well bore surface; providing a surfactant wash treatment fluid that comprises an acid-compatible surfactant, an acid and/or an acid-generating component, and an aqueous fluid; contacting the oil-wet well bore surface with the surfactant wash treatment fluid; allowing the oil-wet well bore surface to become water-wet; and producing fluids from the formation. In another embodiment, the invention provides a surfactant wash treatment fluid for use in a subterranean formation comprising an aqueous fluid, an acid-compatible surfactant, an acid and/or an acid-generating component.

Abstract: Of the many methods and compositions provided herein, in one embodiment, the invention provides a method comprising: providing an oil-wet well bore surface; providing a surfactant wash treatment fluid that comprises an acid-compatible surfactant, an acid and/or an acid-generating component, and an aqueous fluid; contacting the oil-wet well bore surface with the surfactant wash treatment fluid; allowing the oil-wet well bore surface to become water-wet; and producing fluids from the formation. In another embodiment, the invention provides a surfactant wash treatment fluid for use in a subterranean formation comprising an aqueous fluid, an acid-compatible surfactant, an acid and/or an acid-generating component.

Abstract: An improved acidization method is provided in which an aqueous solution comprising one or more esters or polyesters of lactic acid or of glycerol is placed in a well where the esters or polyesters undergo hydrolysis. The hydrolysis of the esters or polyesters occurs at a slower reaction rate than that of several other known acidization esters, such as diethyleneglycol diformate, at temperatures higher than 60° C. or even higher than 100° C. Thus, the solution may be distributed substantially throughout a region in the well where acidization is required before hydrolysis is completed, despite being exposed to relatively high temperatures. The hydrolysis may result in the slow release of an acid that is capable of consuming all or most of an undesirable substance in the well, e.g., a filter cake.

Abstract: An improved acidization solution is provided which comprises water and one or more esters or polyesters of hydroxy acid or of glycerol. The solution may include, for example, ethyl lactate and pure water or a brine. The hydrolysis of the esters or polyesters occurs at a slower reaction rate than that of several other known acidization esters, such as diethyleneglycol diformate, at temperatures higher than 60° C. or even higher than 100° C. Thus, the acidization solution may be distributed substantially throughout a region in a well where acidization is required before hydrolysis is completed, despite being exposed to relatively high temperatures. The hydrolysis may result in the slow release of an acid that is capable of consuming all or most of an undesirable substance in the well, e.g., a filter cake.

Abstract: Metal cross-linked phosphate ester compositions impart fragile progressive gel structure to a variety of oil and invert emulsion-based drilling fluids at neutral or acidic pH. The fluids are useful for drilling wellbores in subterranean formations without need for organophilic clays to suspend drill solids. At greater concentrations, metal cross-linked phosphate ester compositions enhance fluid viscosity for suspending weighting materials in drilling fluids during transport of the fluids, as from a manufacturing or mixing facility to a drilling site.

Abstract: A method and composition for distinguishing native hydrocarbons in a formation from oil-based drilling fluid with nuclear magnetic resonance (NMR) is provided so that NMR may be used in analyzing formation fluids from boreholes drilled with oil-based drilling fluids. In the method, the drilling fluid is doped with oil solubilized paramagnetic species before or during drilling of the borehole. The paramagnetic species cause a shift in the T1 and T2 NMR response of the drilling fluid.

Abstract: In one embodiment, the present invention provides a drilling fluid composition that comprises a surfactant-free emulsion comprising an oleaginous fluid, a fluid that is at least partially immiscible with the oleaginous fluid, and a non-surfactant polymeric emulsifier. In another embodiment, the present invention provides a method of treating a subterranean formation comprising providing a treatment fluid that comprises a surfactant-free emulsion, the surfactant-free emulsion comprising an oleaginous fluid, a fluid that is at least partially immiscible with the oleaginous fluid, and a non-surfactant polymeric emulsifier; and treating the subterranean formation.

Abstract: In one embodiment, the present invention provides a drilling fluid composition that comprises a surfactant-free emulsion comprising an oleaginous fluid, a fluid that is at least partially immiscible with the oleaginous fluid, and emulsion facilitating particles. In another embodiment, the present invention provides a method of treating a subterranean formation comprising providing a treatment fluid that comprises a surfactant-free emulsion, the surfactant-free emulsion comprising an oleaginous fluid, a fluid that is at least partially immiscible with the oleaginous fluid, and emulsion facilitating particles; and treating the subterranean formation.

Abstract: The invention provides aqueous based well drilling and servicing fluids containing a polymer viscosifier with enhanced thermal stability provided by a diacid or diacid salt preferably having about two to about eight carbon atoms, such as, for example, sodium oxalate. The invention also provides a method of enhancing the thermal stability of aqueous based well drilling and servicing fluids containing a polymer viscosifer by adding diacid or diacid salt to the fluids.