China Coal Research Institute
China Coal Technology and Engineering Group Xi’an Research Institute (Group) Co., Ltd.
Tuha Drilling Company of CNPC Western Drilling Engineering Co., Ltd.

碎软煤层渗透性差，瓦斯含量高、压力大，常规穿层钻孔抽采瓦斯时单孔抽采范围小，需密集布孔，钻孔工程量大，易造成采掘接替紧张。基于此，提出穿层钻孔多方位极小半径冲孔造穴抽采瓦斯技术设想，设计了能够固定方向极小半径弯曲的冲孔钻具，通过孔口钻机的推送和孔底施加给射流喷头的阻力实现钻具的固定方向弯曲冲孔，通过动力头握持钻具旋转、固定实现弯曲方位的控制，以此形成穿层钻孔多方位极小半径多分支孔。分析了固定方向弯曲短节弯曲角度、短节长度和钻具曲率半径的关系，为短节的设计提供理论支持；通过测试试验获取了固定方向弯曲钻具的抗拉强度和耐压参数；理论分析了多方位冲孔的可行性，设计了工艺流程；采用试制的钻具在地面进行了模拟试验，在1个主孔中完成了不同方位4个分支孔的冲孔造穴，分支孔孔深6～8 m，证明了技术设想的可行性和钻具结构设计的合理性，能够达到穿层钻孔多方位极小半径冲孔功能要求。

The broken and soft coal seam has high gas content and poor permeability. The single hole drainage radius is small when the conventional through-bed drilling is used for gas drainage, and the drilling engineering volume is large. To this end, a gas extraction technology of crushed soft coal is proposed by radial punching and burrowing. The idea of gas drainage technology by punching holes with multi-direction and minimum radius through-bed drilling is proposed, a punching drilling tool capable of bending in a fixed direction with a minimum radius is designed, through the push of the orifice drilling tool and the resistance exerted on the jet nozzle from the bottom of the hole, the fixed direction bending punching of the drilling tool is realized, and the bending direction is controlled by rotating and fixing the drilling tool held by the power head. In this way, multi-azimuth and multi-branch hole with minimum radius can be formed. The relationship between bending angle, length and radius of curvature of drill tool is analyzed, which provides theoretical support for tool design; the tensile strength and pressure resistance parameters of the tool are obtained through testing; the feasibility of multi-direction punching is theoretically analyzed, and the technological process is designed; the simulation test was conducted on the ground with the trial produced drilling tools, the test results show that the one-way bending drilling tool combined with the hydraulic oscillating impactor can realize the punching of four branch holes in one main hole, the hole depth of the branch hole is 6-8 m. The experiment proves the feasibility of the technical assumption and the rationality of the drilling tool structure design.

天地科技股份有限公司科技创新创业资金专项资助项目（2022-2-TD-ZD007）；中煤科工西安研究院（集团）有限公司科技创新基金资助项目（2019XAYZD06,2020XAYJS10）

庞涛，姜在炳，杜天林，等. 煤矿井下穿层钻孔多方位极小半径冲孔技术[J]. 煤矿安全，2023，54（10）：206−211.

PANG Tao, JIANG Zaibing, DU Tianlin, et al. Multi-azimuth minimal radius punching technology for strata-penetrating borehole of underground coal mine[J]. Safety in Coal Mines, 2023, 54（10）: 206−211.