Patent ID: 9701890
Date: 2017-07-11
CPC Classifications: C09K

Claim:
1. A process for mineral oil production, wherein an aqueous injection fluid comprising at least a water soluble polyacrylamide-(co)polymer dissolved in the aqueous fluid is injected through at least one injection borehole into a mineral oil deposit, wherein the process comprises the following steps: (1) providing a liquid dispersion polymer composition comprising (1-1) providing an aqueous monomer solution comprising acrylamide monomer, acrylic acid monomer, and optionally further ethylenically unsaturated, water soluble comonomers, (1-2) emulsifying the aqueous monomer solution in the organic, hydrophobic liquid (A) in the presence of the at least one surfactant (C1) to form an oil-in-water emulsion, (1-3) adding at least one initiator for radical polymerization to the oil-in-water emulsion to polymerize the acrylamide monomer, the acrylic acid monomer, and optional water soluble monomers, to obtain an inverse emulsion comprising an aqueous phase of the copolymer of polyacrylamide, dissolved or swollen in water, wherein the aqueous phase is emulsified in the organic hydrophobic liquid (A), (1-4) adding the at least one surfactant (C2) to stabilize the inverse emulsion, and (1-5) partially removing water from the inverse emulsion to yield a liquid dispersion polymer composition having a water content of less than 10% by weight, (2) adding at least one activating surfactant (D) to the liquid dispersion polymer composition, (3) mixing the liquid dispersion polymer composition comprising one activating surfactant (D) with an aqueous fluid, thus obtaining an aqueous injection fluid comprising 0.05% by weight to 0.5% by weight of the dispersion polymer, based on the total amount of all components of the injection fluid, and (4) injecting the aqueous injection fluid into the mineral oil deposit through at least the one injection borehole and crude oil is withdrawn from the mineral oil deposit through at least one production borehole.