Method for strengthening regional gas extraction through hydro-thermal coupling fracturing

Abstract

The invention discloses a method for strengthening regional gas extraction through hydro-thermal coupling fracturing. The method comprises steps as follows: firstly, a main fracturing hole, branch fracturing holes and lead holes are sequentially formed in a coal seam roadway through construction, the main fracturing hole is formed in the central position of an equilateral triangle, the opening positions of the branch fracturing holes are distributed at three vertexes of the equilateral triangle separately, the borehole bottom locations of the branch fracturing holes are converged in a center line of the equilateral triangle, the lead holes are located in a circle with the main fracturing hole serving as a center of the circle, and the radius of the circle is 5-15 m; fracturing equipment comprises water injection equipment and a powder injection device, and the water injection comprises an intelligent water tank and a fracturing pump. Quicklime powder in the powder injection device is injected into the main fracturing hole and the branch fracturing holes through underground air pressure; the water injection equipment performs hydraulic fracturing on the main fracturing hole, the quicklime powder is carried by high-pressure water to enter cracks, meanwhile, the quicklime powder and water have a thermal reaction to generate a large amount of heat, and hydro-thermal coupling fracturing is realized; with the implementation of the method for strengthening the regional gas extraction through the hydro-thermal coupling fracturing, the regions influenced by fracturing are increased, the concentration of extracted gas is increased, the effect is remarkable, and demands of work such as regional gas treatment in a coal mine site and the like are met.

Description

technical field [0001] The invention relates to a hydrothermal coupling fracturing enhanced regional gas drainage method, which belongs to the technical field of regional gas control in underground coal mines, and is especially suitable for hydrothermal coupling fracturing operations for regional gas control in deep high gas outburst coal seams. Background technique [0002] The Chinese Academy of Engineering's "National Energy Development Strategy 2030-2050" report proposes that the annual output of coal will be controlled at 3 billion tons in 2050, and coal will be the dominant energy source in my country for a long time. However, the geological conditions of my country's coal mines are complex, high-gas coal seams account for 50%-70%, and high-gas low-permeability coal seams account for about 70% of them. The occurrence characteristics of high gassy and low permeability coal seams in my country are microporosity, low permeability and high adsorption, which often lead to a...

AI Technical Summary

Problems solved by technology

[0003] However, the existing coal seam hydraulic fracturing technology has problems such as unstable technical effect, insufficient pressure relief, and low extraction efficiency.

The main reason is that the traditional hydraulic fracturing technology has insufficient fracture expansion and has not realized the regional fracture network.

Moreover, the existence of water after the implementation of traditional hydraulic fracturing technology blocks the channel of gas flow, which has the effect of inhibiting gas desorption, diffusion and permeation, leading to the gradual limitation of hydraulic fracturing technology

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