Methods for reducing loss of wellbore fluid to formation may include pumping an oil-based wellbore fluid into the wellbore, where the wellbore includes an oleaginous continuous phase and a plurality of modified brine phases dispersed in the oleaginous continuous phase.

A wellbore fluid may include an oleaginous fluid forming a continuous phase; a non-oleaginous fluid forming a discontinuous phase; at least one emulsifier stabilizing an emulsion of the non-oleaginous continuous phase within the oleaginous continuous phase; and at least one viscosifier dispersed into the oleaginous continuous phase in a concentration of at least 4 ppb; wherein upon subjecting the wellbore fluid to shear rate of at least 10,000 s.sup.−1, the emulsion is disrupted and the non-oleaginous fluid contacts the at least one viscosifier, thereby solidifying the wellbore fluid.

A wellbore fluid may include an oleaginous fluid forming a continuous phase; a non-oleaginous fluid forming a discontinuous phase; at least one emulsifier stabilizing an emulsion of the non-oleaginous continuous phase within the oleaginous continuous phase; and at least one viscosifier dispersed into the oleaginous continuous phase in a concentration of at least 4 ppb; wherein upon subjecting the wellbore fluid to shear rate of at least 10,000 s.sup.−1, the emulsion is disrupted and the non-oleaginous fluid contacts the at least one viscosifier, thereby solidifying the wellbore fluid.

The invention provides Formula I compounds, and its compositions, wherein HG, X, L, Y, m, and n are defined in the specification, as fluid efficiency and flow back enhancers for use in a method of treating subterranean formations.

A subterranean treatment fluid may include an invert emulsion including a clarified diutan-based gelled aqueous internal phase and a mineral oil-based external phase, and an acid composition. The acid composition may include at least one acid selected: formic acid, acetic acid, propionic acid, lactic acid, glycolic acid, and combinations thereof, at least one acid-generating compound selected from: an ester; an aliphatic polyester; an ortho ester; a poly(ortho ester); an ortho ether; a poly(ortho ether); a lactide; a poly(lactide); a glycolide; a poly(glycolide); an ε-caprolactone; a poly(ε-caprolactone); a hydroxybutyrate; a poly(hydroxybutyrate); an anhydride; a poly(anhydride); an aliphatic carbonate; an aliphatic polycarbonate; an amino acid; a poly(amino acid), and combinations thereof, or a combination of the at least one acid and the at least one acid-generating compound. The subterranean treatment fluid may have a density less than water.

A subterranean treatment fluid may include an invert emulsion including a clarified diutan-based gelled aqueous internal phase and a mineral oil-based external phase, and an acid composition. The acid composition may include at least one acid selected: formic acid, acetic acid, propionic acid, lactic acid, glycolic acid, and combinations thereof, at least one acid-generating compound selected from: an ester; an aliphatic polyester; an ortho ester; a poly(ortho ester); an ortho ether; a poly(ortho ether); a lactide; a poly(lactide); a glycolide; a poly(glycolide); an ε-caprolactone; a poly(ε-caprolactone); a hydroxybutyrate; a poly(hydroxybutyrate); an anhydride; a poly(anhydride); an aliphatic carbonate; an aliphatic polycarbonate; an amino acid; a poly(amino acid), and combinations thereof, or a combination of the at least one acid and the at least one acid-generating compound. The subterranean treatment fluid may have a density less than water.

The present invention relates to a method for increasing oil recovery from an oil-bearing formation including the following successive stages of treating the formation: injecting an invert emulsion in a volume of 3-5 m.sup.3/m of perforated interval thickness followed by squeezing down an acidic composition or a composition containing a nonionic surfactant in a volume of 2-3 m.sup.3/m of perforated interval thickness to the formation, injecting a highly stable direct emulsion containing a colloidal solution of silicon dioxide nanoparticles in a volume of 3-7 m.sup.3/m of perforated interval thickness followed by squeezing down a liquid from a reservoir pressure maintenance system to the formation.

An oil-based drilling fluid and method of preparing an oil-based drilling fluid are disclosed. The oil-based drilling fluid comprising a base oil continuous phase, an aqueous discontinuous phase, and at least one rheology modifier. The at least one rheology modifier including an alkaline-earth diamondoid compound. The method of preparing the oil-based drilling fluid including mixing a base oil, at least one emulsifier, and at least one wetting agent to form a first mixture, adding and mixing at least one rheology modifier into the first mixture to form a second mixture, adding and mixing at least one fluid-loss control additive into the second mixture to form a third mixture, adding and mixing a brine solution into the third mixture to form a fourth mixture, and adding and mixing a weighting additive into the fourth mixture to form the oil-based drilling fluid.

Some embodiments described herein relate to methods comprising providing a proposed invert emulsion formulation, wherein the proposed invert emulsion formulation comprises an oil phase, an aqueous phase, and a particulates fraction comprising a first sub-fraction and a second sub-fraction, wherein the first sub-fraction comprises high-gravity particulates and the second sub-fraction comprises low-gravity particulates; calculating an initial associative stability value of the proposed invert emulsion based on the degree of association between the aqueous phase and the particulates fraction comprising both the first sub-fraction and the second sub-fraction; manipulating the proposed invert emulsion based on the initial associative stability value so as to produce an associatively stable invert emulsion having a final associative stability value in the range of between about 50% and about 100%; and introducing the associatively stable invert emulsion into a subterranean formation.

Some embodiments described herein relate to methods comprising providing a proposed invert emulsion formulation, wherein the proposed invert emulsion formulation comprises an oil phase, an aqueous phase, and a particulates fraction comprising a first sub-fraction and a second sub-fraction, wherein the first sub-fraction comprises high-gravity particulates and the second sub-fraction comprises low-gravity particulates; calculating an initial associative stability value of the proposed invert emulsion based on the degree of association between the aqueous phase and the particulates fraction comprising both the first sub-fraction and the second sub-fraction; manipulating the proposed invert emulsion based on the initial associative stability value so as to produce an associatively stable invert emulsion having a final associative stability value in the range of between about 50% and about 100%; and introducing the associatively stable invert emulsion into a subterranean formation.