Instant recoverable slippery water for shale gas reservoir

Abstract

The invention relates to instant recoverable slippery water for a shale gas reservoir. The slippery water consists of the following components in percentage by weight: 0.02-0.1 percent of a friction-reducing agent, 0.2-2.0 percent of potassium chloride, 0.1-0.5 percent of a cleanup additive, 0.1-0.5 percent of an anti-swelling agent and the balance of water, wherein the friction-reducing agent is polyacrylamide or a polyacrylamide derivative of which the molecular weight is 5*105-1*106; the cleanup additive consists of 0.5-2.0 percent by mass of a fluorocarbon surfactant, 10-15.0 percent by mass of a low molecular alcohol solvent, 3.0-5.0 percent by mass of a high molecular alcohol additive, 10.0-20.0 percent by mass of a technical grade hydrocarbon chain surfactant and the balance of water; and the anti-swelling agent is a cation polyquaternary salt, poly-quaternary phosphate or a poly-quaternary sulfate. The slippery water can be fully dissolved and swelled within 20-30 seconds for forming a uniform system without oxidizing a gel breaker, damage to the crack diversion capability can be reduced, a cracking reverse discharge liquid can be recycled, and waste liquid treatment cost is lowered.

Description

technical field [0001] The invention relates to a recyclable fracturing fluid used in fracturing and stimulation of shale natural gas wells, in particular to a recyclable slick water using polyacrylamide or polyacrylamide derivatives as a drag reducing agent. Background technique [0002] Fracturing stimulation is required in the development of low-permeability reservoirs. Commonly used fracturing fluids use natural or synthetic polymers as thickeners, and water or brine as solvents. In order to facilitate the carrying and fracturing of proppants, the viscosity is high. However, for ultra-low permeability reservoirs, such as shale, the use of common fracturing fluids for fracturing stimulation is not only costly but also harmful. Therefore, slick water fracturing fluid is usually used for stimulation in the development of shale reservoirs. However, the current slick water has the following disadvantages: ①The swelling time of the current slick water is relatively long, espe...

AI Technical Summary

Problems solved by technology

However, the current slick water has the following disadvantages: ①The swelling time of the current slick water is relatively long, especially for drag reducers with high molecular weight, the swelling time is 10-20 minutes, which is difficult to meet the needs of online preparation for large-scale fracturing of shale; ②Slick water After hydraulic fracturing, about 15-30% of the liquid will flow back, which will pollute the environment, and the treatment cost of the flowback liquid will be high