Mechanical Analysis And Structural Optimization Of Automatic Vertical Drilling System

Automatic vertical drilling system can effectively solve the problem of oblique speed anti complex formation in current oil drilling process.A typical utomatic vertical drilling system generally consists of the information measuring devices,mechanical actuator control circuit which includes hydraulic system.The system is very sensitive to the downhole operating conditions,which highly challenges the safety of the automatic vertical drilling system and the drilling string due to the complex downhole conditions involving severe vibration.Based on basic theory of drill string dynamics,the drill pipe bending deformation is analyzed by considering the wellbore and drill rod gap distance and other factors.And the bending deflection of the drill string under the horizontal vibration condition and the stress distribution are obtained.Then,the safety analysis of drill string structure is conducted,and the resonance frequency of drill string vibration and the fatigue strength of drill string are analyzed.A theoretical method to improve the safety of drill string is developed.Based on the theory of drill string safety,the safety of the automatic vertical drilling system is studied and the corresponding aspects influencing the system safety are found out and improved.The numerical model the automaticvertical drilling system and drill string are established by using finite element software Considering the real drilling process,vibration modal analysis and structural mechanical analysis are conducted respectively for the key components of the automatic vertical drilling system,The axial and transverse shock absorber are designed for measurement and control,and the accelerometer seismic is also improved based on the analysis results.Besides,finite element analysis is conducted for centering ring and spring-based hold-down system.Analysis of the safety of these parts and corresponding design optimization of the important components effectively reduce the vibration intensity of automatic vertical drilling system,then greatly improve the safety of automatic vertical drilling system.