A method of drilling in a subterranean formation. A method may include providing a direct emulsion drilling fluid comprising an aqueous fluid, an oil, and a polysorbate emulsifier; circulating the direct emulsion drilling fluid from a surface, through a wellbore, and back to the surface; and extending the wellbore in the subterranean formation while circulating the direct emulsion drilling fluid.

A method of drilling in a subterranean formation. A method may include providing a direct emulsion drilling fluid comprising an aqueous fluid, an oil, and a polysorbate emulsifier; circulating the direct emulsion drilling fluid from a surface, through a wellbore, and back to the surface; and extending the wellbore in the subterranean formation while circulating the direct emulsion drilling fluid.

Quaternary ammonium compounds and methods of using such compounds to, for example, break oil-in-water emulsion treatment fluids are provided. In some embodiments, such methods include introducing a quaternary ammonium compound into an oil-in-water emulsion treatment fluid that comprises an oleaginous phase and an aqueous phase; and centrifuging at least the portion of the oil-in-water emulsion treatment fluid to separate at least a portion of the oil-in-water emulsion treatment fluid into an oleaginous fluid and an aqueous fluid.

Quaternary ammonium compounds and methods of using such compounds to, for example, break oil-in-water emulsion treatment fluids are provided. In some embodiments, such methods include introducing a quaternary ammonium compound into an oil-in-water emulsion treatment fluid that comprises an oleaginous phase and an aqueous phase; and centrifuging at least the portion of the oil-in-water emulsion treatment fluid to separate at least a portion of the oil-in-water emulsion treatment fluid into an oleaginous fluid and an aqueous fluid.

Methods and compositions comprising an emulsion or a microemulsion for use treating an oil and/or gas well are provided. In some embodiments, the emulsion or the microemulsion comprises an aqueous phase, a solvent, a surfactant comprising alkyl polyglycoside, an alcohol, and, optionally, one or more additives.

Methods and compositions comprising an emulsion or a microemulsion for use treating an oil and/or gas well are provided. In some embodiments, the emulsion or the microemulsion comprises an aqueous phase, a solvent, a surfactant comprising alkyl polyglycoside, an alcohol, and, optionally, one or more additives.

Drilling fluid mixtures are described herein that are stable oil-in-water emulsions. Also described herein are surfactant packages for stabilizing such emulsions. The surfactant packages use an alkyl ether anion comprising an alkyl portion, an anionic head group, and an ether portion between the alkyl portion and the anionic head group.

Drilling fluid mixtures are described herein that are stable oil-in-water emulsions. Also described herein are surfactant packages for stabilizing such emulsions. The surfactant packages use an alkyl ether anion comprising an alkyl portion, an anionic head group, and an ether portion between the alkyl portion and the anionic head group.

A method of reducing a density of a density of a stable emulsion drilling fluid may comprise providing a stable emulsion drilling fluid comprising: an aqueous liquid; a biopolymer; an emulsifier; solid particulates; and an oil; wherein the stable emulsion drilling fluid is capable of remaining in quiescent storage at approximately 70° F. and atmospheric pressure without phase separation for about 8 hours or longer; circulating the stable emulsion drilling fluid though a drill string and annulus; adding additional oil to the stable emulsion drilling fluid to decrease the density of the stable emulsion drilling fluid and produce a reduced density stable emulsion drilling fluid; and circulating the reduced density stable emulsion drilling fluid though the drill string and the annulus.

A method of reducing a density of a density of a stable emulsion drilling fluid may comprise providing a stable emulsion drilling fluid comprising: an aqueous liquid; a biopolymer; an emulsifier; solid particulates; and an oil; wherein the stable emulsion drilling fluid is capable of remaining in quiescent storage at approximately 70° F. and atmospheric pressure without phase separation for about 8 hours or longer; circulating the stable emulsion drilling fluid though a drill string and annulus; adding additional oil to the stable emulsion drilling fluid to decrease the density of the stable emulsion drilling fluid and produce a reduced density stable emulsion drilling fluid; and circulating the reduced density stable emulsion drilling fluid though the drill string and the annulus.