Meikuang Anquan (Jul 2022)
New integrated technology of “drilling-protecting-measuring” borehole in soft-fragmentized coal seam with high gas
Abstract
Soft-fragmentized coal seam is generally characterized by complex tectonic stress, high gas pressure, poor permeability, and easy crushing of coal body. In the construction of gas extraction borehole, borehole is easy to collapse, outburst and cause unstability of the hole wall, which will cause many problems such as drilling difficults, frequent accidents in the borehole, inadequate hole depth and borehole blockage. The technology of safe, efficient and precise borehole construction, borehole protection and borehole measurement in soft-fragmentized coal seam with high gas has always been the major requirements and research hotspot for gas control in soft-fragmentized coal seam. Aiming at the problems faced by borehole construction technology of gas drainage in soft-fragmentized coal seam, a new integrated borehole construction technology of “borehole construction, borehole protection and borehole measurement” is proposed. Through technical improvement, the three separate construction steps of “borehole construction, borehole protection and borehole measurement” are transformed into both borehole protection of placing screen pipe and borehole measurement of measuring borehole trajectory are achieved in the drilling construction process. Compared with the conventional borehole construction method, the new construction technology can improve the safety and efficiency of soft-fragmentized coal seam borehole construction, and effectively avoid the problem that borehole protection operation and borehole measurement operation cannot be carried out due to borehole collapse problem. The new construction technology is applied in the mining area belongs to Huaibei Mining Area, the practice shows that the new integrated borehole construction technology greatly improve completion borehole rate of drilling construction in soft-fragmentized coal seam with high gas, greatly reduces the occurrence of accidents in borehole. It provides a new construction technique and method for the drilling of gas drainage in soft-fragmentized coal seam with high gas.
Keywords
