Research on data transmission system of acoustic wave while drilling based on OFDM

Logging while drilling is to transmit down-hole measurement data to the surface timely and accurately to ensure the normal production. Drilling data transmission system includes mud pulse and electromagnetic wave. The transmission rate of these methods is only tens of bits per second. To solve the problems of slow transmission rate, low accuracy and long waiting time for drilling data, an acoustic wireless communication system based on orthogonal frequency division multiplexing (OFDM) is developed. The hardware and software design of the acoustic wireless communication system has been completed, and experiments have been carried out. The communication channel is drilling fluid, a frequency selective fading channel with Gaussian white noise and obvious multipath effect. OFDM can be used to solve the adverse effects of these problems on signal transmission. Schmidl-Cox algorithm is used for signal synchronization. Error control coding adopts CRC32 algorithm. The experimental results show that the transmission rate of BPSK mapped OFDM signal can reach 250 kbit/s when the bit error rate is 10(-3). Compared with the traditional wireless communication system, an acoustic wireless communication system based on drilling fluid has the advantages of high data transmission rate, low bit error rate and strong anti-multi-path fading ability.

Automated summary

Logging while drilling uses an acoustic wireless communication system to transmit drilling data to the surface, solving the issues of slow data transmission and low accuracy in traditional wireless communication systems.