Research and Application of Point-type Acidification Fracturing Technology for Enhancing Permeability in Low Permeability Coal Seams
To solve the problem of permeability in mineral rich coal seams,a point-type acidification fracturing technology for enhancing permeability was proposed based on the mechanism of point-type fracturing and acid enhanced permeability of coal bodies,and the acid ratio suitable for Sanyuan Coal Mine was determined through scanning electron microscopy experiments.The field test results show that the average gas extraction flow and concentration of point-type acidizing fracturing drilling group is 3.65 times and 1.72 times of that of common drilling group,1.32 times and 1.06 times of that of point-type hydraulic fracturing drilling group,and the anti-permeability effect of point acidizing fracturing is obviously better than that of point-type hydraulic fracturing.In addition,the crack initiation pressure and liquid injection amount of the anti-reflection coal body under the same conditions are lower than that of the point-type hydraulic fracturing.The point-type acidizing fracturing achieves the fixed-point,low-flow,large-range and rapid anti-reflection of the coal body.The integration of the physical anti-reflection and chemical anti-reflection modes greatly improves the development degree of the pore and fracture structure of the coal body and its overall connectivity,which is conducive to the migration and efficient extraction of gas in the coal body.
point-type acidification fracturingscanning electron microscopy experimentacid ratiotransverse crackmicroscopic pore structure
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