A kind of unconventional oil and gas reservoir slick water fracturing drag reducer and preparation method thereof

Abstract

The invention discloses a drag reducer for slickwater fracturing on unconventional oil and gas reservoirs and a preparation method of the drag reducer, and belongs to the technical field of chemicals for the petroleum industry. The drag reducer for slickwater fracturing on the unconventional oil and gas reservoirs comprises components in percentage by mass as follows: 45%-65% of polyacrylamide, 10%-12% of potassium oleate, 5%-7% of hydroxypropyl oleamide betaine, 3%-5% of sorbitol polyoxylethylene ether, 3%-5% of nonyl phenol polyoxyethylene ether, 2% of a discharge aiding agent and the balance of 15# white oil. The slickwater drag reducer has higher drag reduction property and system stability, and the fluid flow velocity change gradient is reduced through synergism of a polymer and a viscoelastic surfactant to realize the drag reduction action; and besides, the polymer molecular weight is smaller, a molecular film is prevented from forming and blocking rock pores, the surface / interfacial tension of oil and water can be reduced with adding of the surfactant, fracturing backflow can be facilitated, the nitrogen lift effect after fracturing can be increased, and permanent harm of slickwater to the reservoirs is effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of chemicals used in the petroleum industry, and relates to a drag reducer for unconventional oil and gas fracturing and a preparation method thereof, in particular to a drag reducer for slick water fracturing of unconventional oil and gas reservoirs and a preparation method thereof. Background technique [0002] With the upsurge in the exploitation of unconventional oil and gas resources, the slickwater fracturing technology suitable for the exploitation of unconventional reservoirs such as low permeability and low porosity has been increasingly popularized. Slick water is to add a certain amount of chemical additives such as drag reducer, clay stabilizer, bactericide and metal salt to the aqueous solution to form a pressure reducing agent with low viscosity, shear resistance, small damage and good drag reduction. cracking liquid system. Slippery water fracturing was first used for fracturing and stimulati...

AI Technical Summary

Problems solved by technology

Under the admiration of the fracturing method of "Thousands of sand, Wanfang liquid, low sand ratio, and large displacement", domestic research on slick water drag reducers has just started. Invention patent 201110401452.7 discloses a shale gas reservoir Instant recyclable slick water, the drag reducer used is 5 million to 10 million polyacrylamide or polyacrylamide derivatives, and the added amount is 0.02 to 0.1%. The system has a large amount of use, and the molecular weight of the drag reducer is too high , the drag reduction performance is average, and the filter membrane is formed to block the pores, which is easy to cause permanent damage to the reservoir

Therefore, it is not conducive to the full play of the reservoir protection and the drag reduction performance of the drag reducer.

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