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), 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.

A tight oil reservoir CO.sub.2 flooding multi-scale channeling control system and a preparation method, including nanoscale CO.sub.2 responsive worm-like micellar systems and micron-scale CO.sub.2 responsive dispersion gel, are provided. The nanoscale CO.sub.2 responsive worm-like micelle system is prepared by CO.sub.2 reactive monomers and organic anti-ion monomers stirred in water. The micron-scale CO.sub.2 responsive dispersion gel is made of acrylamide, a responsive monomer, a silane coupling agent modified hydroxylated multi-walled carbon nanotubes as raw materials, cross-linked in water. The tight oil reservoir CO.sub.2 multi-scale channel control system, has strong flow control ability during CO.sub.2 displacement, and high-strength carbon nanotubes are introduced into the micro-scale CO.sub.2 responsive dispersion gel, which effectively improves the strength and long-term stability of the dispersion gel, significantly enhances the sealing effect on cracks, and after displacement of the CO.sub.2 of the system, the worm-like micelles revert to spherical micelles with good responsive reversibility.

A tight oil reservoir CO.sub.2 flooding multi-scale channeling control system and a preparation method, including nanoscale CO.sub.2 responsive worm-like micellar systems and micron-scale CO.sub.2 responsive dispersion gel, are provided. The nanoscale CO.sub.2 responsive worm-like micelle system is prepared by CO.sub.2 reactive monomers and organic anti-ion monomers stirred in water. The micron-scale CO.sub.2 responsive dispersion gel is made of acrylamide, a responsive monomer, a silane coupling agent modified hydroxylated multi-walled carbon nanotubes as raw materials, cross-linked in water. The tight oil reservoir CO.sub.2 multi-scale channel control system, has strong flow control ability during CO.sub.2 displacement, and high-strength carbon nanotubes are introduced into the micro-scale CO.sub.2 responsive dispersion gel, which effectively improves the strength and long-term stability of the dispersion gel, significantly enhances the sealing effect on cracks, and after displacement of the CO.sub.2 of the system, the worm-like micelles revert to spherical micelles with good responsive reversibility.

The present disclosure discloses methods for preparing an in-situ nano emulsifier. The preparation method may include obtaining a solution by dissolving hydrated ferric chloride (or ferric chloride) and hydrated ferrous sulfate (or ferrous sulfate) into deionized water at a first temperature; obtaining an ethanol solution dissolved with an oil-soluble surfactant by dissolving an oil-soluble surfactant into ethanol at a second temperature; and adding a certain volume of ammonia water and the ethanol solution dissolved with the oil-soluble surfactant in the solution to obtain an in-situ nano emulsifier. The in-situ nano emulsifier may be applied to development of the oil reservoir through an application process. The application process may include preparing a nano emulsifier solution and a surfactant solution; sequentially injecting the surfactant solution and the nano emulsifier solution into a formation; and injecting a spacer liquid slug into the formation for replacement.

The present disclosure discloses methods for preparing an in-situ nano emulsifier. The preparation method may include obtaining a solution by dissolving hydrated ferric chloride (or ferric chloride) and hydrated ferrous sulfate (or ferrous sulfate) into deionized water at a first temperature; obtaining an ethanol solution dissolved with an oil-soluble surfactant by dissolving an oil-soluble surfactant into ethanol at a second temperature; and adding a certain volume of ammonia water and the ethanol solution dissolved with the oil-soluble surfactant in the solution to obtain an in-situ nano emulsifier. The in-situ nano emulsifier may be applied to development of the oil reservoir through an application process. The application process may include preparing a nano emulsifier solution and a surfactant solution; sequentially injecting the surfactant solution and the nano emulsifier solution into a formation; and injecting a spacer liquid slug into the formation for replacement.

Process for producing aqueous polyacrylamide concentrates by polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel, comminuting said aqueous polyacrylamide gel and mixing it with an aqueous liquid, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous polyacrylamide concentrate hold in a suitable transport unit from a location A to a location B. Modular, relocatable plant for manufacturing aqueous polyacrylamide, wherein the units of the plant are located at two different locations A and B.

Process for producing aqueous polyacrylamide concentrates by polymerizing an aqueous solution comprising at least acrylamide thereby obtaining an aqueous polyacrylamide gel, comminuting said aqueous polyacrylamide gel and mixing it with an aqueous liquid, wherein the manufacturing steps are allocated to two different locations A and B and the process comprises the step of transporting an aqueous polyacrylamide concentrate hold in a suitable transport unit from a location A to a location B. Modular, relocatable plant for manufacturing aqueous polyacrylamide, wherein the units of the plant are located at two different locations A and B.

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.

A method may include: introducing a treatment fluid into a stream, the treatment fluid comprising: a base fluid and a supramolecular host guest product, wherein the supramolecular host guest product comprises a treatment fluid additive and a supramolecular host molecule, wherein the supramolecular host molecule is not covalently bonded to the treatment fluid additive.