Study On The Mechanism Of Stick-Slip Vibration Of Drill Bit And Active Disturbance Rejection Vibration Controller Design

Drilling is an important part of oil and gas exploration.Friction between the drill string,drill bit,and rock formations inevitably causes vibrations,which can have adverse effects on drilling efficiency and equipment life,and even lead to drill bit failure.Among them,stick-slip vibration is a common type of vibration,which has periodic and aperiodic vibrations and is difficult to predict and control.Typically,the control of stick-slip vibration can be achieved by optimizing the design of the drill bit,controlling the speed and pressure of the drill string,and other methods.However,the complexity of the drilling site conditions and the uncertainty of the mechanism of drilling stick-slip vibration pose great challenges to vibration control.Therefore,strengthening the theoretical research of drilling stick-slip vibration,exploring vibration mechanisms and advanced control strategies,and designing reliable vibration controllers are of great significance for improving drilling efficiency,reducing drill bit damage rates,and enhancing the safety and stability of drilling processes.The development of modern control theory has significant advantages in solving practical problems in existing engineering environments.Various improved classic control theories and new control theories have gradually been applied in drilling engineering.Currently,research on drilling stick-slip vibration at home and abroad is mainly carried out from two directions: one is to design new drilling tools,explore new drilling methods,and develop new drilling materials from the hardware equipment perspective;the other is to design reliable drilling controllers based on the improvement of existing tools and suppress drill bit stick-slip vibration from the control theory perspective.This paper aims to suppress stick-slip vibration during the drilling process and carries out related research work by designing drilling controllers based on theoretical analysis and simulation experiments.The main work of this paper includes:(1)By studying the working mechanism of the drilling system,such as the top drive torque output,the drill string torque transmission,and the rock breaking effect of the drill bit,corresponding drill tool working mechanism models were established.Critical vibration conditions of stick-slip vibration were derived based on relevant theories such as regenerative cutting effects and rock failure criteria,and the identification methods,influencing factors,and general anti-vibration methods of stick-slip vibration were summarized.A stick-slip vibration simulation model was established,and vibration failure simulation analysis was carried out.(2)Based on vibration theory analysis and the active disturbance rejection control principles,a fuzzy prediction compensation active disturbance rejection controller was designed.A cascade control structure of ADRC+P control was designed to improve the controller’s responsiveness.A Smith predictive compensation combined with an ESO structure was designed to improve the controller’s error compensation ability.Fuzzy SEF control law was designed to improve the controller’s adaptability.Finally,the stability and robustness of the controller were verified through simulation experiments.(3)Based on the Simulink simulation platform and SIEMENS S120 frequency converter and its matching drive control system,simulation and physical simulation vibration experiments were designed.The control effect of the designed controller was verified by comparing the velocity before and after stick-slip vibration control,the angle displacement comparison,and the torque change comparison.The experimental results showed that the designed controller has good vibration suppression effect and provides certain reference value for the design of assisted shock absorption drilling tools and stick-slip vibration control systems.