Various embodiments disclosed relate to surfactant compositions for treatment of subterranean formations and produced oil. In various embodiments, the present invention provides a method of treating a subterranean formation including placing in the subterranean formation a surfactant composition. The surfactant composition includes an alkanolamide surfactant and an alkoxylated alcohol surfactant. The surfactant composition also includes an ionic surfactant, a nonionic surfactant, or a combination thereof.

Compounds are identified that act as crystallization suppressants when added to clear brine fluids, significantly lowering the true crystallization temperatures of the brines, and allowing for higher salt content in clear brine fluids. The crystallization suppressants of the invention also allow for the preparation of higher density zinc free brines. Crystallization suppressant blends are also identified that allow for the preparation of high density clear brine fluids with lower viscosities.

Compounds are identified that act as crystallization suppressants when added to clear brine fluids, significantly lowering the true crystallization temperatures of the brines, and allowing for higher salt content in clear brine fluids. The crystallization suppressants of the invention also allow for the preparation of higher density zinc free brines. Crystallization suppressant blends are also identified that allow for the preparation of high density clear brine fluids with lower viscosities.

A quaternized alkoxylated polyethylene amine can be used in a variety of industries, including the oil and gas servicing industry, as a laundry detergent, the personal care industry, as an industrial cleaner, paint, or coating, and mining operations industry. A treatment fluid comprises: a base fluid; and the surfactant. A method of treating a subterranean formation comprises introducing the treatment fluid into a well, wherein the well penetrates the subterranean formation.

A method of improving rheological properties of a divalent brine based downhole treatment fluid at an elevated temperature comprises adding to the divalent brine based downhole treatment fluid a rheological modifier, which comprises a carboxylic acid ester, or a phosphate ester blended with an ethoxylated glycol, or a combination comprising at least one of the foregoing in an amount effective to improve the rheological properties of the divalent brine based downhole treatment fluid at a temperature of greater than about 200° F. The divalent brine based downhole treatment fluid comprises calcium bromide, calcium chloride, zinc bromide, zinc chloride, or a combination comprising at least one of the foregoing.

A method of improving rheological properties of a divalent brine based downhole treatment fluid at an elevated temperature comprises adding to the divalent brine based downhole treatment fluid a rheological modifier, which comprises a carboxylic acid ester, or a phosphate ester blended with an ethoxylated glycol, or a combination comprising at least one of the foregoing in an amount effective to improve the rheological properties of the divalent brine based downhole treatment fluid at a temperature of greater than about 200° F. The divalent brine based downhole treatment fluid comprises calcium bromide, calcium chloride, zinc bromide, zinc chloride, or a combination comprising at least one of the foregoing.

A method and system for pressurizing and stimulating a formation with a parent well therethrough, the method including storing and de-liquefying liquefied natural gas (LNG) at an on-site location near the parent well, injecting a first stream of de-liquefied LNG into the parent well to pressurize the formation, and injecting a second stream of de-liquefied LNG into the parent well at a fracturing pressure sufficient to fracture the pressurized formation.

A method for in situ acid stimulation of a subterranean formation that contains a hydrocarbon reservoir may include contacting the formation with an acidizing fluid comprising an aqueous fluid, a sulfonyl chloride, and a mutual solvent, wherein upon exposure to formation temperatures, the sulfonyl chloride and aqueous fluid hydrolyze the sulfonyl chloride, thereby producing hydrochloric acid.

A method and a system for in-situ remediation of recalcitrant organic and inorganic contaminants in an environmental medium are disclosed. Dissolved gases from water and an oil are removed to form degassed water and a degassed oil. The degassed water and the degassed oil are mixed to form a surfactant-free oil-in water emulsion. The surfactant-free oil-in-water emulsion is injected into the environmental medium, thereby producing anaerobic conditions to cause indigenous anerobic bacteria to biodegrade residual concentrations of the contaminants in the environmental medium.

A method and a system for in-situ remediation of recalcitrant organic and inorganic contaminants in an environmental medium are disclosed. Dissolved gases from water and an oil are removed to form degassed water and a degassed oil. The degassed water and the degassed oil are mixed to form a surfactant-free oil-in water emulsion. The surfactant-free oil-in-water emulsion is injected into the environmental medium, thereby producing anaerobic conditions to cause indigenous anerobic bacteria to biodegrade residual concentrations of the contaminants in the environmental medium.