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.

Various embodiments disclosed relate to demulsifier compositions for treatment of subterranean formations or produced petroleum comprising an emulsion. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in the subterranean formation a demulsifier composition. The demulsifier composition includes at least one resin of formula (I) and at least one compound of formula (II).

Various embodiments disclosed relate to demulsifier compositions for treatment of subterranean formations or produced petroleum comprising an emulsion. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in the subterranean formation a demulsifier composition. The demulsifier composition includes at least one resin of formula (I) and at least one compound of formula (II).

A wellbore fluid may include a base fluid, and a ground weight material comprising barite and quartz and having a d.sub.50 between about 4 and 8 microns and a d.sub.90 between about 15-25 microns. The ground weight material of the wellbore fluid may have a specific gravity of less than or equal to about 4.2.

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.

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An emulsion is mixed with fibers while the emulsion is moving through a surface tubing using a venturi. The fiber/emulsion mixture is injected into a pressurized tank and the pressurized fiber/emulsion mixture is injected from the pressurized tank into a desired location in a wellbore. Pumps and pressure boosters may be used to move the fluid.

An emulsion is mixed with fibers while the emulsion is moving through a surface tubing using a venturi. The fiber/emulsion mixture is injected into a pressurized tank and the pressurized fiber/emulsion mixture is injected from the pressurized tank into a desired location in a wellbore. Pumps and pressure boosters may be used to move the fluid.

Methods for treating an oil well having a wellbore. The methods involve injecting a microemulsion into the wellbore to increase formation crude oil production by the well. The microemulsion comprises water, a first type of solvent and a first type of surfactant. The microemulsion includes a continuous water phase.

Methods for treating an oil well having a wellbore. The methods involve injecting a microemulsion into the wellbore to increase formation crude oil production by the well. The microemulsion comprises water, a first type of solvent and a first type of surfactant. The microemulsion includes a continuous water phase.

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.