Continuous Wave Mud Pulse Generator System Design And Transmission Characteristics Research

Continuous wave mud pulse information transmission system plays an important role in oil and gas field development technologies such as measurement while drilling and logging while drilling.Compared with other information transmission methods,continuous wave mud pulse information transmission system has the advantages of lower cost,longer transmission distance and faster transmission speed.In this thesis,considering the specific underground environment,theoretical research,simulation analysis and specific experimental methods are adopted to carry out the following works:Firstly,according to the existing mathematical model of the valve port,an optimization model of the valve port contour was established.The maximum correlation coefficient is the objective function in the optimization model,and the optimal valve port contour was obtained by means of Fluent for optimization design.In addition,the results of pressure wave spectrum analysis are consistent with the results of the optimization algorithm,it proved the correctness of the optimization algorithm.Finally,compared with the existing literature results,the optimized stator and rotor valve orifice is better than the existing design scheme.Secondly,according to the basic principles of fluid dynamics and the unsteady friction theory,the transmission model of continuous wave mud pulse in drilling fluid channel was constructed.The governing equation was discretized and solved by the characteristic line method and the first-order finite difference method.The pressure wave,it was generated by the optimized valve port profile,was taken as the input of transmission model.The optimal transmission frequency of the pressure wave signal is determined by the spectrum analysis of model results.Moreover,according to the confirmed valve port profile and the optimal transmission frequency,the rotor load can be known.the load generation module is constructed in Simulink.Then,based on the direct torque control method,the rotor drive control system model of mud pulse generator was constructed and the optimal control parameters were determined through the simulation results to achieve the optimal control effect.Futhermore,by analyzing the problems existing in the drive system of the continuous wave mud pulse generator,the sensenseless algorithm based the model reference adaptive control technology was designed for the direct torque control model of the motor.The simulation results show that the control system has good speed and torque following performance.Finally,the motor drive system is verified experimentally,and the towing mode test platform was built.The generator direct torque control system experiment and the generator sensorless direct torque control experiment are respectively carried out.The results,consistent with the simulation,proved that the motor drive control system has good performance.