Gas outburst elimination method combining downhole drilling, surface fracturing and downhole drainage

Abstract

The invention discloses a gas outburst eliminating method combining underground drilling, ground fracturing and underground extraction, which comprises the following steps of: selecting a gas outburstregion to be eliminated, arranging underground well position and carrying out drilling and cementing; laying a fracturing pipeline to a target coal seam region, performing ground fracturing on the coal seam, and modifying the target coal seam; drilling a gas extraction hole in a well, establishing a gas underground rapid extraction and exhaust system through the gas extraction hole and a fractured well, and completing the complete extraction and exhaust of the gas. According to the method, by combining the underground drilling, the ground fracturing and the underground extraction, the underground drilling and ground fracturing are combined to cause stress reconstruction of the coal seam, the local stress concentration is destroyed, the effective stress of the stratum is reduced, and a large artificial fracture network system is formed in the coal seam, the network system is communicated with the coal rock primary fracture and rock cutting, the coal rock permeability is improved, gas desorption is promoted, migration of the gas to a well bore for discharging is accelerated, the gas content in coal seam is reduced, the method has important theoretical and practical significance.

Description

technical field [0001] The invention belongs to the field of low-permeability and high-gas content coal mine gas rapid control and outburst elimination, and more specifically relates to a gas outburst elimination method combining underground drilling, surface fracturing and underground drainage. Background technique [0002] Coalbed methane (gas) is a mineral resource that mainly exists in coal rocks in the form of adsorption, and is separated from coal rocks through decompression and desorption. Most coal seams in my country have the characteristics of high gas and low permeability, and with the increase of coal seam mining depth, the ground stress continues to increase, the air permeability coefficient of coal seams decreases, and the permeability of coal seams further decreases, which seriously restricts the extraction of coal seam gas. The effect has affected the normal mining and replacement of the mine. [0003] Due to the characteristics of high gas and low permeabili...

AI Technical Summary

Problems solved by technology

[0004] Ground drilling, ground fracturing, ground drainage or ground underground combined drainage are affected by the ground, and the ground drilling site is not easy to determine, and the technical method has high construction costs and long extraction time, which cannot meet the needs of coal mine production; Due to the limitation of underground space, the construction scale and construction displacement of underground fracturing are limited by underground drilling and underground fracturing, which affects the fracturing effect and cannot meet the needs of rapid outburst elimination in coal mines.

Images