The Research Of Transfers Model Based On MWD Data Acoustic Distan Transmission System

Study on the transmission charactristics of acoustic along drillstrings can help toexploit the high speed data transmission techniques using drillstrings,rescarch the acousticlogging instrument while drilling.All these have practical application values for upgradingthe intelligent drilling technique in our conutry.It’s very useful for MWD data transmission using drillstrings as the channel for carrierpropagation.The low frequency acoustic propagation characteristics in periodic drillstringwere calculated using finite elements method and theory computation method in this paper.The results show that periodic drillstrings have pass band and stop band just like the combfilter. The position and width of pass band and stop band were determined by the length ofthe drill pipe and coupling. The results of the theoretical analysis and the actual resultsachieved good consistency, preliminary proved that the analysis method of reliability andvalidity.This topic is base on the transmission model of drillstrings acoustic telemetry system,acoustic transmission of the drill pipe and collar as the research object. According to the Sparameters of the system transfer function which derived from the drillstrings Acoustictransmission model, use electronics, computer and other related areas of knowledge,Convert the system transfer function to circuit model,, which uses circuit to replace andSimulate the acoustic transmission properties in drill string, Simulate the circuit, Thenfinally simulate the acoustic transmission properties in drill string for visualization.This topic for acoustic waves in periodic drill rod in the transmission characteristics ofthe future, for downhole acoustic transmission technology research has a certain referencemeaning.