井下瓦斯抽采钻孔机械造穴技术研究

Study of Mechanical Cavity-forming Technology for Underground Gas Drainage Hole Drilling

为了解决低渗透性煤层瓦斯抽采困难的问题,通过理论分析和数值模拟研究了提高钻孔瓦斯抽采效率的主要途径,借鉴煤层气洞穴完井工艺技术,研制了以钻机给进和旋转为动力、适用于井下瓦斯抽采钻孔的开合机械臂式造穴工具,形成了可在井下煤层瓦斯抽采钻孔内定点位置实现Φ600mm洞穴的工艺技术.在芦岭煤矿的2组造穴钻孔工程试验表明,机械造穴技术能够明显提高钻孔瓦斯抽采效果,与同一地点的常规瓦斯抽采钻孔相比,造穴钻孔单孔瓦斯抽采浓度提高了2.31～4.00倍,纯瓦斯流量提高了2.63～5.11倍.

In order to solve the problem of difficult gas drainage from the coal seam with low permeability, study was carried out on the main ways for improving gas drainage efficiency by theoretical analysis and numerical simulation,coal-bed methane well completion technology was used for reference, a cavity-forming tool with a retractable arm was developed, which took the drill feed and rotation as the power and was suitable to drill gas drainage holes, with this cavity-forming tool, Φ600 mm cavity-forming technology can be achieved at a fixed position in underground gas drainage holes. The cavity-forming drilling test in Luling Coal Mine showed that the mechanical cavity-forming technology for coal gas drainage drilling can significantly improve the efficiency of gas drainage, and compared with the conventional gas drainage drilling, the gas concentration of a single hole with the cavity-forming drilling technology increased by 2. 31 to 4. 00 times and the pure gas flow increased by 2. 63 ~ 5. 11 times.