Technical Research Of Short-distance Communication Of Acoustic Wave In Drill Pipe

The scientists and engineers are always confused by the communication problem betweenthe rotating stable platform and the relatively static MWD. Based on a large number ofdomestic and foreign literature； this paper detailly analyses the transmission mechanism ofacoustic wave in the irgid medium, discusses the method of Duiffng chaotic detection, andproposes the short-distance communication technology of the incentive acoustic wave with thedownhole drill pipe.The expeirment of the short-distancc communication discovers that the amplitude oftransversal wave is stronger than longitudinal stimulation, chooses the dirving method ofsquare wave by comparing the waveform of which the sine wave, square wave and trianglewave dirve the vibrator. The simulation test successfully dctccts the weak signal amplitude ofacoustic wave on the base of building acoustic model and Duffing chaotic system. Theacoustic transmitting circuit achieves3channels A/D conversion, uses2ASK signalmodulation. The acoustic receiving circuit adopts a kind of RC iflter and voltage follower,improves the circuit’s iflter function, enhances the circuit’s load ability, and achieves theconversion of signal quantization. Finally, the serial communication between51MCU and PCis ifnished by transforming circuits of the RS-232level and debugging little helper of serialport.In conclusion, this paper fundamentally realizes the short-distancc communication ofdownhole acoustic wave. Its correctness and feasibility arc proved by comprehensivelyanalysing the expeirmental results.