Development and Application of Fixed Length and Location Hole Sealing Technology

In order to explore more simple and effective technology of drilling and sealing in gas extraction,the fixed length and location hole sealing and the self-plugging on both ends sealing sack which was used for that was developed, on the basis of the analysis of the routine technology of drilling and sealing in gas extraction. The technology was simple and quick, a single - pressure grouting seal and fixed length and location of borehole pressurized sealing was realized, the sealing technology had better sealing effect, higher efficiency and lower labor intensity. The comparison test was carried out in Longshan Coal Mine by using this technology and original hole sealing technology. The results showed that the new sealing technology can improve the quality of hole sealing, the average extraction concentration of single hole is increased by about 37.5%, the gas concentration decay of drainage borehole is slower, the borehole service cycle is longer, and the proportion of higher concentration borehole is higher.