Driving Control And Experiment Research Of Acoustic Communication In Drill Pipe

Automatic steerable drilling system can achieve real-time measurement of wellbore trajectory attitude parameters.The borehole information,measured by variable sensors is transmitted to measurements-while-drilling(MWD)by short-range wireless communication,then to the ground station.Downhole acoustic communication is a better data transmission technology,and the data of rotating stable platform can be transferred to relatively static MWD.In fact,acoustic signal attenuates heavily while propagating in drill pipe.This paper designs programmable excitation control circuit,and studies the single drill acoustic transmission sensitivity to pulse signal with adjustable duty.Adjustable pulse circuit,integrated power amplification circuit and power circuit are included in the programmable excitation control circuit.SCM(Single-Chip Microcomputer)outputs pulse signal with adjustable frequency and duty,and the vibration exciter is driven to excite the drill pipe for producing acoustic signal after the power amplifier circuit.4independent keys of the SCM system are used to set the frequency and duty of the pulse,and LCD1602 can display in real time.A short distance acoustic transmission experiment system is built on the 1.28 m long drill pipe.The pulse voltage as driving signal is used for experiment.Vibration exciter drives drill pipe in radial mode.The senor receive acoustic signal at the other end,then the signal is processed by the constant current adapter.Finally,signal waveform is shown on the oscilloscope.The driving signal with variable frequency,varying their duty from 10% to 90%,generates different results for the research of the acoustic signal sensitivity.Experimental results show that the proposed programmable exciting control circuit can be applied to the acoustic transmission system of short distance drill pipe,and 20%~30% duty driving signal is the best in the acoustic transmission.