A Study Of Underground Instrument Based On Wireless Acoustic Telemetry

Now, the oil has become an important energy base and the economic lifeline of the world,all countries attach great importance to mining and excavation of petroleum resources It isimpotant to achieve important parameters of underground timely and Accurately for petroleumexploration and development. The underground information transmission can be summed upfor wired transmission method and wireless transmission method But, traditional cabletransmission has many drawbacks, including annulus test method, bundled test method, andoptical transmission method. Therefore, wireless transmission technology and methodsbecome a focus for researchers. Acoustic telemetry method has the advantages of low cost,simple method of operation, called a ideal transmission. In this paper, we reserch wirelessacoustic telemetry underground instrument according to the theory of acoustic propagation inthe tubing strings, mainly including the following:Firstly, in the article, we derived expression of the reflection coefficient and thetransmission coefficient of acoustic waves in the tubing string transmission using the matrixmethod. Under the given tube parameters, we used the matlab software programming to getthe the relationship simulation diagram of the transmission coefficient T and the acoustictransmission frequency,which verified that the sound waves has dressing filtering transmissioncharacteristics—passband and stopband alternately appears in the tubing string. Then,weverified the periodic frequency characteristics of tubing string once again, and also found thefeature of largest energy and minimum attenuation for200Hz signal by sweeping test.Secondly, this article describes the design of underground instrument system fromhardware design and software design aspects in detail. In terms of hardware design, the articlefirst introduces the overall design of the underground instrument system,then gives a detaileddescription of various parts of the circuit schematic of the system, including preamplifiercircuit, real-time clock circuit, drive circuit of the transducer and the acoustic transducer.Software design includes the main program and each subroutine.Finally, it shows that the design can meet the requirements of underground acoustic signaltransmission and achieve the design requirements by testing underground instrument system.