High-pressure gas-liquid microbubble anti-permeability method for low-permeability coal seam

Abstract

A high-pressure gas-liquid micro-bubble permeability-increasing method for a low permeability coal seam includes the steps: (1) first drilling out a fracturing hole and a testing hole respectively ina perforating layer, with the hole bottom being in the fractured coal seam; (2) making a fracturing pipe into the fracturing hole and the testing hole, connecting the fracturing pipe inside the fracturing hole with a high-pressure pipeline, and sealing the fracturing hole and the testing hole with high pressure; (3) connecting a hydraulic fracturing equipment and a gas fracturing equipment to a high-pressure pipeline; (4) using the gas fracturing equipment for continuous fracture to the coal seam, and ending the gas fracture when the pressure in the test hole increases; (5) carrying out the hydraulic fracture, and ending the fracturing operation when there is water spillover or obvious pressure increase in the test hole; (6) releasing the high-pressure water and the high-pressure gas inside the two holes, connecting into a gas drainage pipe network, and carrying out the gas drainage. The high-pressure gas-liquid micro-bubble permeability-increasing method for the low permeability coalseam not only can increase the permeability of the coal seam evenly, but also can solve the problem that the residuary water prevents gas from being released after a single hydraulic fracture, so thatthe average extraction flow of a single hole increases by more than 60%, and the time of extracting coal seam is reduced by 30%.

Description

technical field [0001] The invention belongs to the technical field of underground gas control in coal mines, and in particular relates to a high-pressure gas-liquid microbubble anti-permeability method for low-permeability coal seams. Background technique [0002] With the increase of mining depth, the amount of gas gushing out is increasing, and the threat of gas explosion and gas outburst is becoming more and more serious. The main measure to solve the gas problem in the mining process of high gassy and low permeability coal seams is to implement coal seam gas drainage in advance, and the coal seams mined in more than 95% of the outburst mines in my country belong to low permeability coal seams, and the coal seam permeability coefficient is only 0.004~0.04 m 2 / (mpa 2 · d), gas drainage is very difficult, so improving the permeability of the coal seam is the key to the effectiveness of outburst prevention measures in the pre-gas extraction area. [0003] At present, the...

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Problems solved by technology

[0004] Aiming at the problems existing in the prior art, the present invention provides a high-pressure gas-liquid microbubble anti-permeability method for low-permeability coal seams, which can uniformly increase the gas permeability of the coal seam, and can effectively solve the problem of residual moisture hindering gas release after single hydraulic fracturing problem, it can also significantly improve the extraction effect

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