Research on Multi-mode Auto-drilling Technology of AC Variable Frequency Rig

In view of the fact that single mode auto-drilling can not meet the requirements of different targets and different drilling stages for automatic drilling, several kinds of auto-drilling technology in multi-mode are studied, including constant rate of penetration (ROP) control, constant weight on bit (WOB) control, constant pump pressure control, constant power control and constant torque control, and corresponding auto-drilling control systems are constructed respectively. In view of the complexity of drilling process and the difficulty in establishing mathematical model, the active disturbance rejection control (ADRC) strategy is proposed after analyzing the relationship among various factors affecting the drilling. The algorithm does not need the precise mathematical model of the control object, and can modify the control parameters in real time through self-learning. The experiment results show that the control effect is good, the auto-drilling can be realized on the basis of multi-mode target, and the control algorithm is also universal.