Adaptive Torque Control for Top Drive During Drill String Reversal in Ultra-Deep Wells

This study addresses stick-slip vibration, pipe sticking, and drill string reversal in ultra-deep well drilling through an adaptive top drive torque control method. The solution integrates drill string-friction coupling mechanisms with fuzzy PID control. A time-varying torque transmission model is developed by establishing torsional vibration differential equations, analyzing down hole friction distribution, and incorporating bottom hole assembly (BHA) structural characteristics. The model combines real-time surface torque monitoring with friction inversion data to reveal spatiotemporal evolution patterns of drill string-wellbore contact stress. A compound control logic featuring “stepped torque loading-instantaneous reverse release” is designed. An adaptive regulation algorithm based on fuzzy PID theory achieves precise speed-torque coordination. Researchers construct a multi-physics coupling simulation model integrating top drive, drill string, and formation interactions. Validation tests are conducted using complex drilling scenarios from 9,626–9,643 m intervals in Well TK-1. Key findings demonstrate: (1) Torque transmission shows second-scale time-delay effects. (2) Dynamic regulation activates when speed deviation exceeds 10 rpm, reducing stick-slip response time by 63% compared to traditional PID control and emergency shutdowns by 60%. (3) Top drive spindle reversal is effectively suppressed. The method resolves three technical challenges: time-delay compensation in torque transmission, adaptive control under complex friction conditions, and transient torque fluctuation suppression. Field applications confirm its effectiveness in maintaining drilling continuity while preventing equipment damage. This research provides theoretical and technical support for intelligent torque control in ultra-deep wells exceeding 9,000 m depth.