Research On Underground Acoustic Two-way Wireless Transmission Relay System

In recent years,downhole sonic wireless transmission technology has attracted more and more researchers' attention due to its advantages such as convenience,high efficiency,and low cost.It has been applied in fields such as drilling while drilling,well testing,and reservoir dynamic monitoring.However,the attenuation of acoustic signals at various types of pipe couplings,such as drill pipes and tubing,has resulted in a limited transmission distance,which seriously limits its promotion.In response to this problem,the thesis focuses on the design of underground acoustic transmission system based on two-way wireless relay.This paper first introduces the basic principles of wireless transmission of downhole acoustic waves,analyzes the frequency characteristics and attenuation characteristics of acoustic waves transmitted along the drill pipe,and studies the formation mechanism of noise during the propagation of acoustic waves along the drill pipe.In addition,for downhole acoustic relay transmission,a two-way relay transmission model based on amplification and forwarding was established,and the time-sharing two-way transmission method of acoustic relay was studied.The corresponding simulation model is designed,and FSK modulation is used to verify and analyze the acoustic wave transmission model along the drill pipe and the two-way relay model based on time-sharing transmission.On this basis,according to the principle of decoding and forwarding relay system,the processing flow of collecting,amplifying,demodulating and forwarding the sound wave signal captured by the relay system is designed.And using dsPIC33 EV high-temperature digital signal controller as the main control chip of the relay system,the corresponding transmission circuit,receiving circuit,data acquisition circuit,charge amplification and modulation and demodulation circuit and other relay system modules are optimized and designed.Finally,a simulation experiment platform was built to carry out the simulation experiment and analysis of the underground acoustic wave wireless relay transmission system.The experimental results show that the hardware circuit of the relay transmission system designed in this paper is stable and can effectively extend the transmission distance of the underground acoustic wave transmission system and realize the wireless two-way transmission of acoustic wave relay.