| The cable logging remote transmission system is a classic remote communication system for the field of oil logging,and cable logging plays a very important role in the field of logging.The communication medium for cable logging uses various wired logging cables,which often have high transmission rates as wired communication.Nowadays,cable logging systems generally use a combination of Discrete Multi Tone technology and various encoding methods to improve the transmission rate of communication.This thesis focuses on the remote transmission logging system of the high-power power supply instrument for sidewall coring of China Oilfield Services Limited.Analyze the system principle and transmission signal characteristics of the remote transmission system,in order to improve the anti-interference performance of the system as much as possible.Improving the transmission rate of the system and enhancing its reliability while ensuring a certain bit error rate.In the system,the interference and noise introduced by system transmission are key factors that affect the bit error rate and transmission rate.Therefore,the introduction and generation mechanism of interference and noise are the key points of this study.After understanding these interferences,it is necessary to determine a simple,fast,and efficient interference suppression algorithm to suppress interference in the system as much as possible.The main content of this article is as follows:1.Research on cable logging systems.Understand the communication scheme of the system,analyze the generation of its signals,and the modulation and demodulation methods of the uplink and downlink.Study the composition and structure of the wellbore coring system in order to understand the entire communication system.2.Analyze and model the communication channel and interference of the system.By studying the various parameters of the cable and the functional modules through which the signal is transmitted,the channel response of cable communication is determined,and then select an effective transmission bandwidth.Afterwards,the source and characteristics of the interference signal are analyzed,and the noise model and probability distribution of the interference signal are determined by analyzing the mechanism and principle of interference generation.This section provides a prerequisite for subsequent interference suppression algorithms.3.Research on compressed sensing algorithm.Understand the principle and theoretical basis of compressed sensing algorithm,and research and analyze the existing Matching pursuit algorithms such as Orthogonal Matching Pursuit,Compressive Sampling Matching Pursuit,and Sparsity Adaptive Matching Pursuit,so as to determine the algorithm with better efficiency and performance.Finally,based on the existing interference model,an interference suppression algorithm for the logging remote transmission system in this thesis was proposed and simulated for analysis.4.Research on interference suppression for actual logging systems.Determine the process of the entire system and the interference suppression algorithm used.This interference suppression algorithm can weaken narrowband interference in cable logging systems and effectively reduce the system’s bit error rate.At the same time,the interference suppression algorithm was implemented and its error compared with the simulation results. |
PDF Full Text Request