A drag reducer for inverse emulsion hydraulic fracturing modified with hydrophobic and oil-repellent fluorine-containing groups

Abstract

The invention relates to a hydrophobic and oleophobic fluorine-containing group-modified drag reducer for hydraulic fracturing of an inverse emulsion, and belongs to the technical field of application of chemical agents in oil-gas field engineering. The hydrophobic and oleophobic fluorine-containing group-modified drag reducer is prepared by initializing inverse emulsion polymerization with a water-soluble monomer A1, a fluorine-containing monomer A2, a mutual solvent A3, water A4, an oil phase B and a free radical initiator C. According to the drag reducer, a water-phase mixture is dispersed into an oil phase represented by mineral oil or paroline to form a 'W / O' inverse emulsion; a small fluorine-containing segment with low surface energy and friction coefficient and the minimal surface tension in a solid material is introduced; the drag-reducing property of an original drag reducer is reserved; the drag reduction efficiency can reach 70% when the drag reducer is applied to hydraulic fracturing; meanwhile, the affinity between drag reducer molecules and the affinity between the drag reducer molecules and a reservoir rock are reduced by introduction of the fluorine-containing group; the drainage assisting performance and the reservoir protection performance after the hydraulic fracturing process are improved; and the problems that the drag reducer for shale oil and gas development at present is poor in flowback performance, serious in reservoir damages and high in biotoxicity are solved.

Description

technical field [0001] The invention relates to a water-repellent, oil-repellent and fluorine-containing group-modified anti-emulsion drag reducer for hydraulic fracturing, which belongs to the technical field of application of oil and gas field engineering chemical agents. Background technique [0002] In recent years, with the extensive exploration and development of shale oil and gas, slickwater fracturing for the purpose of improving reservoir permeability has received more and more attention. Slick water refers to the working fluid in which a small amount of drag reducer and other chemical additives are added to clear water or salt water. This working fluid is injected underground at high pressure and quickly, fracturing oil and gas reservoirs, increasing permeability, and increasing oil and gas production. However, there are a series of problems in the use of drag reducers for shale oil and gas development, such as poor flowback performance, serious reservoir damage, ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a kind of technology that 1) is used in "W / O" inverse emulsion polymerization In the water phase where the water-soluble monomer is dissolved, a small amount of fluorine-containing monomer and mutual solvent are introduced, and the water-soluble drag reducer macromolecules are modified with fluorine-containing groups through copolymerization; 2) and the presence of co-solvent makes the fluorine-containing The monomer is soluble in the water phase, and the introduction of a small amount of fluorine-containing monomer units does not negatively affect the water solubility and drag reduction efficiency of the drag reducer macromolecule. The inverse emulsion modified by the hydrophobic, oil-repellent and fluorine-containing groups is used for hydraulic fracturing. Drag reducer