The Research on the Establishment and Simulation of Intelligent Drill String Cables Based on Nonuniform Transmission Line Theory

Abstract

The cable transmission line has more obvious advantages in long-distance information transmission, and is suitable for the transmission of various MWD signals during drilling. The research on the information transmission pattern of the cable transmission line will be the focus of intelligent drill string. According to the characters of the intelligent drill string, combing with the nonuniform transmission line theory, and considering the effect of temperature variation on the impedance of the smart drill string, the distribution parameters of the cable transmission line has been analyzed. On the basis of the two port network system, the transfer function and the transport matrix of the nonuniform transmission line have been obtained, and the model of nonuniform transmission line impedance of the intelligent drill string cable has been established. In order to verify the feasibility of the established model, the communication channel model has been built utilizing the MATLAB/Simulink software. Through experiment simulation and result analysis, the error rate curves under different parameters have been obtained, the transmission rate and transmission distance of different signals have been explored, and the influence of modulation and demodulation on data transmission quality has been studied, which provides a certain reference for the information transmission pattern of the intelligent drill string.