Compositions emulate oil based fluids include an aqueous phase and an organic internal phase, which creates an osmotic membrane within the aqueous continuous phase. The osmotic membrane allows hydration-dehydration mechanisms to be in place and control interactions between formation and fluid, where the non-aqueous phase is composed of glycerols, polyglycerols, poly hydroxyl alcohols, monosaccharide derivatives, polysaccharide derivatives, or mixtures and combinations thereof, while the aqueous phase contains additives that impart different inhibiting mechanisms to the overall composition, where the additives include, without limitation, amphoteric polymers, potassium and/or sodium salts up to saturation and/or acrylamides.

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.

Some embodiments described herein provide a method comprising method comprising providing an oil-in-water emulsified spacer fluid comprising a binary surfactant mixture, solvent non-aqueous base fluid, and an aqueous base fluid, wherein the binary surfactant mixture comprises a surfactant and an amphiphilic co-surfactant, wherein the surfactant is present in an amount in the range of from about 0.5% to about 30% by weight of the oil-in-water emulsified spacer fluid and wherein the amphiphilic co-surfactant is present in an amount in the range of from about 0.5% to about 30% by weight of the oil-in-water emulsified spacer fluid, and introducing the oil-in-water emulsified spacer fluid into a subterranean formation comprising a residual non-aqueous fluid therein, wherein the binary surfactant mixture in the oil-in-water emulsified spacer fluid emulsifies at least a portion of the residual non-aqueous fluid.

Some embodiments described herein provide a method comprising method comprising providing an oil-in-water emulsified spacer fluid comprising a binary surfactant mixture, solvent non-aqueous base fluid, and an aqueous base fluid, wherein the binary surfactant mixture comprises a surfactant and an amphiphilic co-surfactant, wherein the surfactant is present in an amount in the range of from about 0.5% to about 30% by weight of the oil-in-water emulsified spacer fluid and wherein the amphiphilic co-surfactant is present in an amount in the range of from about 0.5% to about 30% by weight of the oil-in-water emulsified spacer fluid, and introducing the oil-in-water emulsified spacer fluid into a subterranean formation comprising a residual non-aqueous fluid therein, wherein the binary surfactant mixture in the oil-in-water emulsified spacer fluid emulsifies at least a portion of the residual non-aqueous fluid.

Processes are provided for conformance control in an enhanced oil recovery operation. These processes may for example provide for the use of cellulose nanocrystals (CNCs), for example desulfated CNCs, or chitin nanoparticles, for example having an average maximum dimension of 1 m. These CNCs or chitin nanoparticles may be used to generate a CNC-stabilized oil in water emulsion, which may then be injecting into a zone of a porous subsurface formation. The injected CNC or chitin-stabilized emulsion may be allowed to form strong droplet networks with by resting in situ in the zone of the porous subsurface formation, so as to increase the viscosity of the rested injected CNC or chitin-stabilized emulsion. These emulsions may be used as a selective phase blocking agent or relative permeability modifier, as the strength of the droplet network is governed by the dielectric constant of the surrounding fluid.

Processes are provided for conformance control in an enhanced oil recovery operation. These processes may for example provide for the use of cellulose nanocrystals (CNCs), for example desulfated CNCs, or chitin nanoparticles, for example having an average maximum dimension of 1 m. These CNCs or chitin nanoparticles may be used to generate a CNC-stabilized oil in water emulsion, which may then be injecting into a zone of a porous subsurface formation. The injected CNC or chitin-stabilized emulsion may be allowed to form strong droplet networks with by resting in situ in the zone of the porous subsurface formation, so as to increase the viscosity of the rested injected CNC or chitin-stabilized emulsion. These emulsions may be used as a selective phase blocking agent or relative permeability modifier, as the strength of the droplet network is governed by the dielectric constant of the surrounding fluid.

The application relates to compositions comprising di-fatty-alkyl or -alkenyl polyalkylamines of the general formula (I) or (II), to a process for their preparation which involves a cyanoethylation step and a hydrogenation step, and their use as demulsifiers for oil-in-water emulsions, corrosion inhibitor, fuel additive, anti-scaling agent, asphalt additive, enhanced oil recovery agent for oil-wells, cutting-oil additive, and anti-static agent. The product show good performance combined with a favourable viscosity profile. ##STR00001##

The application relates to compositions comprising di-fatty-alkyl or -alkenyl polyalkylamines of the general formula (I) or (II), to a process for their preparation which involves a cyanoethylation step and a hydrogenation step, and their use as demulsifiers for oil-in-water emulsions, corrosion inhibitor, fuel additive, anti-scaling agent, asphalt additive, enhanced oil recovery agent for oil-wells, cutting-oil additive, and anti-static agent. The product show good performance combined with a favourable viscosity profile. ##STR00001##

Methods and compositions comprising an emulsion or a microemulsion and a polymer for use in an oil and/or gas well are provided. In some embodiments, the emulsion or the microemulsion comprises water, a solvent, and a surfactant, and optionally, one or more additives. In certain embodiments, the polymer comprises a copolymer comprising an acrylamide.

Methods and compositions comprising an emulsion or a microemulsion for use in various aspects of the life cycle of an oil and/or gas well are provided. In some embodiments, the emulsion or the microemulsion comprises water, a solvent, and a surfactant, and optionally, one or more additives.