Torsional Pendulum Drag Reduction Technology for Directional Drilling of Ultra Deep Hole in Underground Coal Mine

Abstract

Aiming at the problems such as low efficiency and depth limit of directional drilling caused by the support pressure of drilling tools in the directional drilling of ultra-deep hole in underground coal mine, learning from the twist drilling technology in oil drilling, this paper analyzes the technological principle, the adaptability and operation feasibility of directional drilling in underground coal mine, describes its specific operation flow, and carries out field test in 5th area of Baode Coal Mine. The test results show that the resistance reduction technology of torsional pendulum drilling is applicable to directional ultra-deep hole drilling in underground coal mine, and the applicable range is 2 000 m to 3 000 m for directional ultra-deep hole drilling. The drag reduction effect is obvious in the process of solid drilling, and the change range of tool surface at hole bottom is small, which is mainly affected by the reverse torque of screw motor.

Keywords

• drilling technology
• ultra-deep hole
• directional drilling
• torsional drilling
• torsional pendulum drag reduction