Method for improving coal seam permeability based on acidification means

Abstract

The invention discloses a method for improving coal seam permeability based on an acidification means. The method comprises the steps that before working face stoping, a downward consequent layer along a coal seam and tending to parallel construction in a working face return air roadway and an upward consequent layer along the coal seam and tending to parallel construction in a working face transportation roadway are drilled at intervals of equal hole pitches, drill holes sealed through guiding pipes are filled with an acid solution; the acid solution is prepared from hydrochloric acid, hydrofluoric acid, an acidizing retardance agent, an acidizing corrosion inhibitor, a ferrous stability, an anti-swelling agent and water; after acidification, the acid solution is discharged. By the adoption of the method, the coal seam permeability is improved, carbonate mineral components are dissolved by adopting the hydrochloric acid, and ferric hydroxide precipitate generation is inhibited. Silicate mineral components contained in a coal seam are dissolved by adopting the hydrofluoric acid. The acidizing retardance agent is absorbed on the surface of the coal seam to retard the reaction of the acid solution and the coal seam surface, inhibit the mass transfer velocity of H<+>, prolong the reaction time of the acid solution and the coal seam, increase an effective action distance of the acid and coal seam reaction and achieve the deep acidification purpose.

Description

technical field [0001] The invention relates to the field of mining, in particular to a method for increasing coal seam permeability based on acidification. Background technique [0002] The coal seam permeability directly determines the effect of gas drainage. Due to the poor permeability of coal seams in my country, with the gradual increase of coal mining depth in my country, the mining conditions become more complex, and there are high ground stress, high gas, and high heterogeneity. The characteristics of the coal body are high permeability, low permeability, and low strength. The primary fractures and porosity of the coal body gradually become smaller, and the permeability of the coal seam decreases accordingly. The effective impact range of a single borehole is small, the pre-drainage borehole requires a large amount of work, and the drainage efficiency is low. Conventional gas drainage methods are difficult to play a role. The threat of gas explosion and gas outburst ...

AI Technical Summary

Problems solved by technology

The effective impact range of a single borehole is small, the pre-drainage borehole requires a large amount of work, and the drainage efficiency is low. Conventional gas drainage methods are difficult to play a role. The threat of gas explosion and gas outburst is becoming more and more serious, and low permeability has become a constraint The key factor of coal seam gas drainage, improving the permeability of coal seam is the fundamental way of gas disaster control and resource utilization

[0003] Aiming at the problem of underground gas drainage in low-permeability coal seams, Chinese coal mine researchers have adopted hydraulic fracturing, hydraulic punching, hole reaming technology, hydraulic slotting, N 2 Foam fracturing, CO 2 Physical methods such as foam fracturing to transform the coal seam and change the conductivity of the coal seam consume a lot of manpower, material resources, and financial resources. Some effects have been achieved in some areas, but the transformation effect in some areas is not satisfactory

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