Abstract: Compositions and methods for producing a hydrocarbon from a formation include drilling the formation with a drill-in fluid to form a wellbore and emplacing a fluid loss composition in the wellbore. The fluid loss composition may include an aqueous fluid, a viscosifier, a water soluble polar organic solvent, a delayed acid source having a hydrolyzable ester configured to hydrolyze in situ, and a weighting agent. A viscosity of the fluid loss composition may be reduced by shutting the wellbore for a predetermined time and releasing an organic acid from a time-delayed hydrolysis of the hydrolyzable ester, wherein an amount of delay prior to the time-delayed hydrolysis of the hydrolyzable ester is greater than 1 hour.

Abstract: Drilling fluids were developed including a base fluid, a weighting agent and/or a bridging agent, and a thickening agent, where the weighting agent and/or the bridging agent includes a particulate strontium carbonate having a desired distribution, for weighting agents, the distribution includes particles between 2? and 5000? and for bridging agents, the distribution is constructed from particles having specific sizes. Methods making and using the drilling fluids were also discovered.

Abstract: Compositions for controlling fluid loss may include an aqueous fluid, a viscosifier, a water soluble polar organic solvent, a delayed acid source, and a weighting agent. The composition may further comprise at least one selected from bridging solids, cleaning agent, dispersant, interfacial tension reducer, pH buffer, thinner, or surfactant. Such compositions may be used in producing a hydrocarbon from a formation by drilling the formation with a drill-in fluid to form a wellbore, emplacing the composition in the wellbore, and shutting the well for a predetermined time to allow the viscosity of the fluid loss composition to decrease.

Abstract: Drilling fluids were developed including a base fluid, a weighting agent and/or a bridging agent, and a thickening agent, where the weighting agent and/or the bridging agent includes a particulate strontium carbonate having a desired distribution, for weighting agents, the distribution includes particles between 2? and 5000? and for bridging agents, the distribution is constructed from particles having specific sizes. Methods making and using the drilling fluids were also discovered.

Abstract: A method of gravel packing a hole in a subterranean formation having a filter cake coated on the surface thereof is disclosed. The method may include: injecting into the hole a gravel pack composition comprising gravel and a carrier fluid comprising a base fluid and at least one alkyl glycoside. Also disclosed is a solution including an aqueous fluid, at least one alkyl glycoside, and gravel which may be used as a composition for a gravel pack operation, for example.

Abstract: A method of gravel packing a hole in a subterranean formation having a filter cake coated on the surface thereof is disclosed. The method may include: injecting into the hole a gravel pack composition comprising gravel and a carrier fluid comprising a base fluid and at least one alkyl glycoside. Also disclosed is a solution including an aqueous fluid, at least one alkyl glycoside, and gravel which may be used as a composition for a gravel pack operation, for example.

Abstract: A hydrocarbon drilling fluid system is disclosed including a hydrocarbon fluid and a foaming composition, where the foaming composition includes a polymer, a gelling agent and its cross-linking agent, an optional foaming agent, or mixtures or combinations thereof. Uses of this drilling fluid system in a variety of downhole application are also disclosed.

Abstract: A hydrocarbon drilling fluid system is disclosed including a hydrocarbon fluid and a foaming composition, where the foaming composition includes a polymer, a gelling agent and its cross-linking agent, an optional foaming agent, or mixtures or combinations thereof. Uses of this drilling fluid system in a variety of downhole application are also disclosed.

Abstract: An under-balanced drilling fluid additive is disclosed which reduces reactive shale and/or clay swelling during under-balanced drilling operations, where the additive includes an effective amount of a choline salt. A method for under-balanced drilling is also disclosed including the step of circulating a drilling fluid including an effective amount of a choline salt to reduce reactive shale and/or clay swelling during under-balanced drilling operations.

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 monovalent cation containing well fluid composed of an aqueous brine containing at least 0.6 equivalents per liter of a water soluble monovalent cation salt, is substantially free of divalent cations, and an amount of a starch derivative selected such that the well fluid has the following characteristics: (a) a low shear rate viscosity greater than about 5,000 centipoise; (b) a high shear rate viscosity at 511 sec?1 in the range from about 15 to about 70 centipoise measured at 120° F. is described. The fluid may be formulated to be substantially free of xanthan gums and preferably has less than 0.25 lb/bbl of xanthan gum.

Abstract: An under-balanced drilling fluid additive is disclosed which reduces reactive shale and/or clay swelling during under-balanced drilling operations, where the additive includes an effective amount of a choline salt. A method for under-balanced drilling is also disclosed including the step of circulating a drilling fluid including an effective amount of a choline salt to reduce reactive shale and/or clay swelling during under-balanced drilling operations.

Abstract: A monovalent cation containing well fluid composed of an aqueous brine containing at least 0.6 equivalents per liter of a water soluble monovalent cation salt, is substantially free of divalent cations, and an amount of a starch derivative selected such that the well fluid has the following characteristics: (a) a low shear rate viscosity greater than about 5,000 centipoise; (b) a high shear rate viscosity at 511 sec−1 in the range from about 15 to about 70 centipoise measured at 120° F. is described. The fluid may be formulated to be substantially free of xanthan gums and preferably has less than 0.25 lb/bbl of xanthan gum.

Abstract: A method of treating a well including injecting a thermally stable, substantially water-free well-treating fluid into the well, wherein the well-treating fluid comprises a polymer, a glycol compound, and a salt is disclosed. In another embodiment, a thermally stable, substantially water-free well fluid including a polymer, a diol compound, and a salt is disclosed.

Abstract: High density, thermally stable, brine-based well fluids and methods of using the same are disclosed. In one embodiment a well fluid including water and a salt, the salt including at least one formate salt, wherein the weight-to-volume ratio of the well fluid is within the range of at least 120% to about 400% is disclosed. In another embodiment, a well fluid including water, a viscosifying agent, and a salt, the salt including at least one formate salt, wherein the weight-to-volume ratio of the well fluid is within the range of at least 120% to about 400% is disclosed. A method of treating a well using a well fluid, wherein the well fluid includes water and a salt, the salt including at least one formate salt, wherein the weight-to-volume ratio of the well fluid is within the range of at least 120% to about 400% is also disclosed.

Abstract: A method of treating a well including injecting a well-treating fluid into the well, where the well-treating fluid comprises a glycol compound and an organic liquid, the glycol compound and organic liquid being present in amounts selected to achieve a desired density. In another embodiment, a well fluid including a glycol compound an organic liquid, and a salt, wherein the glycol compound, organic liquid, and salt are present in amounts selected to achieve a predetermined density is disclosed.

Abstract: A method of treating a well including injecting a thermally stable, substantially water-free well-treating fluid into the well, wherein the well-treating fluid comprises a polymer, a glycol compound, and a salt is disclosed. In another embodiment, a thermally stable, substantially water-free well fluid including a polymer, a diol compound, and a salt is disclosed.

Abstract: The present invention relates to methods and compositions for increasing the effective temperature range for viscosified fluids, including particularly fluids that have been viscosified by the addition of a natural or a natural derivative polymer. In one embodiment, the present invention relates to a method for increasing the effective temperature range for a polymer-viscosified fluid used as a well fluid, which includes adding a miscible tertiary, secondary, and/or primary amine compound into a polymer solution. In another embodiment, the present invention relates to a thermally stable well fluid, which includes a polymer, a solvent, and a tertiary, secondary, and/or primaryamine miscible in the solvent.

Abstract: High density, thermally stable, brine-based well fluids and methods of using the same are disclosed. In one embodiment a well fluid including water and a salt, the salt including at least one formate salt, wherein the weight-to-volume ratio of the well fluid is within the range of at least 120% to about 400% is disclosed. In another embodiment, a well fluid including water, a viscosifying agent, and a salt, the salt including at least one formate salt, wherein the weight-to-volume ratio of the well fluid is within the range of at least 120% to about 400% is disclosed. A method of treating a well using a well fluid, wherein the well fluid includes water and a salt, the salt including at least one formate salt, wherein the weight-to-volume ratio of the well fluid is within the range of at least 120% to about 400% is also disclosed.

Abstract: The present invention relates to methods and compositions for increasing the effective temperature range for viscosified fluids, including particularly fluids that have been viscosified by the addition of a synthetic polymer. In one embodiment, the present invention relates to a method for increasing the effective temperature range for a synthetic polymer-viscosified fluid used as a well fluid, which includes adding a miscible tertiary, secondary, and/or primary amine compound into a polymer solution. In another embodiment, the present invention relates to a thermally stable well fluid, which includes a synthetic polymer, a solvent, and a tertiary, secondary, and/or primary amine miscible in the solvent.