This invention provides a concentrated demulsifier composition comprising A) at least 50 wt.-% of a demulsifier, selected from the group consisting of a polymeric nonionic oil-soluble demulsifier for mineral oils, and an alkyl aryl sulphonic acid or its salt, and mixtures thereof, B) 0.1 to 20 wt.-% of a surfactant selected form anionic, cationic, zwitterionic and nonionic surfactants, the surfactant being different from the demulsifier, C) less than 20 wt.-% of a water-immiscible organic solvent, D) 3 to 49 wt.-% of a water-miscible organic solvent and E) 0 to 5 wt.-% of water.

This invention provides a concentrated demulsifier composition comprising A) at least 50 wt.-% of a demulsifier, selected from the group consisting of a polymeric nonionic oil-soluble demulsifier for mineral oils, and an alkyl aryl sulphonic acid or its salt, and mixtures thereof, B) 0.1 to 20 wt.-% of a surfactant selected form anionic, cationic, zwitterionic and nonionic surfactants, the surfactant being different from the demulsifier, C) less than 20 wt.-% of a water-immiscible organic solvent, D) 3 to 49 wt.-% of a water-miscible organic solvent and E) 0 to 5 wt.-% of water.

The invention relates to an inverse polymer emulsion having the particular feature of auto-inverting without any need for the use of an inverting agent and containing a polymer of at least one water-soluble monomer and at least one LCST macromonomer. The invention also relates to the use of the inverse emulsion in the fields of the oil and gas industry, water treatment, slurry treatment, paper manufacturing, construction, mining, cosmetics, textiles, detergents or agriculture.

The invention relates to an inverse polymer emulsion having the particular feature of auto-inverting without any need for the use of an inverting agent and containing a polymer of at least one water-soluble monomer and at least one LCST macromonomer. The invention also relates to the use of the inverse emulsion in the fields of the oil and gas industry, water treatment, slurry treatment, paper manufacturing, construction, mining, cosmetics, textiles, detergents or agriculture.

Some reservoirs have tight oil formations, such as the Changqing reservoir. The surfactant polymer flooding and low tension gas flooding are two potential chemical flooding methods for use in tight oil formations. In these methods, an oil displacement agent, or surfactant, is added. Nonionic surfactants with extended chains (by propylene oxide and ethylene oxide) from dialkyl alcohols or dialkyl amines were tested. A synergistic blend of surfactants was developed between the nonionic surfactants and anionic surfactants that lowers interfacial tension and improves surfactant solubility in water and oil.

Some reservoirs have tight oil formations, such as the Changqing reservoir. The surfactant polymer flooding and low tension gas flooding are two potential chemical flooding methods for use in tight oil formations. In these methods, an oil displacement agent, or surfactant, is added. Nonionic surfactants with extended chains (by propylene oxide and ethylene oxide) from dialkyl alcohols or dialkyl amines were tested. A synergistic blend of surfactants was developed between the nonionic surfactants and anionic surfactants that lowers interfacial tension and improves surfactant solubility in water and oil.

The present invention relates to a process for the preparation of a water-soluble copolymer comprising the step of reacting a monomer (a) of formula (I), (1) wherein Q.sup.1, Q.sup.2, R.sup.1 to R.sup.7 and X have the meaning as indicated in the description and claims with at least one monoethylenically unsaturated, anionic monomer (b), preferably representing a monoethylenically unsaturated monomer comprising at least one carboxy, phosphonate or sulfonate group and salts thereof, preferably their ammonium salts or alkaline-earth metal salts or alkali metal salts; and at least one monoethylenically unsaturated, non-ionic monomer (c). The present invention further relates to a copolymer obtainable by said process and its use in enhanced oil recovery (EOR), a formulation comprising said copolymer and a method of oil production uses said formulation.

The present invention relates to a process for the preparation of a water-soluble copolymer comprising the step of reacting a monomer (a) of formula (I), (1) wherein Q.sup.1, Q.sup.2, R.sup.1 to R.sup.7 and X have the meaning as indicated in the description and claims with at least one monoethylenically unsaturated, anionic monomer (b), preferably representing a monoethylenically unsaturated monomer comprising at least one carboxy, phosphonate or sulfonate group and salts thereof, preferably their ammonium salts or alkaline-earth metal salts or alkali metal salts; and at least one monoethylenically unsaturated, non-ionic monomer (c). The present invention further relates to a copolymer obtainable by said process and its use in enhanced oil recovery (EOR), a formulation comprising said copolymer and a method of oil production uses said formulation.

The present application relates to methods and systems for mitigating condensate banking. In some embodiments, the methods and systems involve altering the wettability of a rock formation in the vicinity of a wellbore for a gas condensate reservoir.

The present application relates to methods and systems for mitigating condensate banking. In some embodiments, the methods and systems involve altering the wettability of a rock formation in the vicinity of a wellbore for a gas condensate reservoir.