ermeability enhancement test of staged hydraulic fracturing of bedding drilling borehole in working face

Abstract

In low permeability and outburst coal seam, the gas in the working face extracted by bedding drilling borehole has the characteristics of large amount of workload and low extraction efficiency. No.15 coal seam of Sijiazhuang Coal Mine belongs to the low permeability outburst coal seam. Staged hydraulic fracturing of bedding drilling borehole was carried out to enhance the extraction in 15301 working face. By using the self-developed drag type double packer section sealing equipment and technology, the fracturing hole can be stably and rapidly sealed, and the whole hole section can be divided into three or more sections for fracturing. Compare the gas drainage effect of drilling in fracture zone and non-fracture zone, the average concentration of fractured area is 35.1%, and that of non-fractured area is 6.0%. The concentration of fractured area is 5.9 times of that of non-fractured area. The pure flow rate of 100 holes in fractured area is 3.6 m3/min, and that in the non-fractured area is 0.3 m3/min. The pure flow rate of 100 holes in the fractured are is 11.2 times of that in the non-fractured area.

Keywords

• mining face
• bedding drilling borehole
• staged hydraulic fracturing
• double packer
• permeability enhancement effect