Research into technology for precision directional drilling of gas-drainage boreholes

Purpose. In order to solve the serious problem of borehole deflection in coal mine gas drainage, precision directional drilling tool has been developed and improved, as well general laws have studied. Methods. By using ordinary pipes, one set two sets tools, gas-drainage boreholes drilled and, subsequently, trajectory parameters measured an inclinometer. Findings. The inclination angle first tends decrease then increase, while azimuth generally increases. is effective, especially when tools. this case, average 100-meter final reduced by 66.0%, 52.3%, 46.5%. Originality. A for its effectiveness confirmed; summarized from overall subsection intervals. Practical implications. research results are great guiding significance preventing deflections further on drilling.