Application research sectional compound-hydraulic technology for enhancing permeability of hole drilled along seam

The hydrodynamic enhancing permeability technology is important means for enhancing gas drainage of coal seam with low permeability.On the basis of analyzing the function characteristic of jet impact of hydraulic slotting technology and compression of hydraulic fracturing technology, and with a view of increasing pressure releasing range of borehole, connecting the fracture network around borehole, and improving gas drainage effect, the sectional compound-hydraulic technology for enhancing permeability of hole drilled along seam is proposed, and the field tests are carried out in the huoerxinhe coal mine.The results show that the borehole diameter increases by 3-4 times and the pressure relief range significantly increases after using the subsection compound-hydraulic technology.The daily drainage purity of single hole increased by 3-4 times in the early stage of drainage.The single hole drainage shows significant attenuation from 10 days to 20 days, the single hole cumulative drainage increased by 4-6 times and the drainage rate of a single hole increased by 3-5 times on 30 days, and the effective control range of borehole drainage is increased.