Low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental method

Abstract

The invention relates to a low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental method belonging to the field of low-permeability coal seam reinforcement anti-reflection technology. The low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental method adopts a low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental device, and comprises the following steps of: (1) installing a monitoring element; (2) measuring the coal permeability before anti-reflection; (3) starting a high-pressure gas impact system for impacting coal briquettes in a circulating way; and (4) measuring the coal permeability after anti-reflection; and the low-permeability coal high-pressure gas cycle pulse fracturing anti-reflection experimental device comprises a coal sample, a blasting cylinder mechanism, a triaxial loading system, a high pressure gas impact system and a coal permeability measurement system.

Description

technical field [0001] The invention belongs to the technical field of enhancement and anti-reflection of low-permeability local coal seams, and in particular relates to an experimental method of low-permeability coal body high-pressure gas circulation pulse cracking for anti-permeability. Background technique [0002] The anti-permeability technologies of low-permeability coal seams in my country mainly include: conventional pressure relief and anti-reflection technologies represented by cross drilling, and enhanced pressure relief and anti-permeability technologies represented by deep hole blasting and hydraulic fracturing. The disadvantage of the conventional pressure relief and antireflection technology is that the drilling volume is large, the extraction time is long, the amount of gas extracted is small, and the antireflection effect is not significant; the disadvantage of the enhanced pressure relief and antireflection technology is that the sparks generated by deep ho...

AI Technical Summary

Problems solved by technology

The disadvantage of the conventional pressure relief and antireflection technology is that the drilling volume is large, the extraction time is long, the amount of gas extracted is small, and the antireflection effect is not significant; the disadvantage of the enhanced pressure relief and antireflection technology is that the sparks generated by deep hole blasting have the potential to cause Potential danger of explosion, and repeated charge blasting is not possible. Most of the explosive energy of the explosive is basically consumed in the pulverized area around the blast hole, which makes the range of anti-reflection of this technology limited.

Although the length of cracks generated by hydraulic fracturing can reach tens of meters, some coal bodies will show significant water sensitivity when exposed to water, making it difficult for the high-pressure water injected into the coal body to discharge, blocking the crack channels, and causing coal The high stress concentration of the coal body, and the crack expansion of the coal body has significant in-situ stress sensitivity, which makes the actual anti-permeability effect of the coal body unsatisfactory

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