Butted Technology Between Underground Directional Drilling Borehole and Vertical Well of Surface U-type Well Group

In order to improve the extraction efficiency of surface coal-bed methane wells, the possibility of realizing the three-dimensional combined extraction of coal-bed methane by butted drilling borehole is verified. Taking a main hole with a depth of 1 544 m butted hole completed in Baode Coal Mine as an example, the design method, design principle and hole depth structure of butted hole trajectory are introduced, the butted connection technology and directional drilling trajectory control technology are studied, and the combined pumping effect of butted hole and surface U-shaped well group is analyzed. The results show that the joint drilling of the underground and the vertical U-shaped wells can improve the extraction efficiency of the surface coal-bed gas wells, which is of exemplary significance for the gas control and efficient development and utilization of the coal mine.