Downhole Compression Algorithm for Remote Detection Acoustic Logging Data Based on Adaptive Differential Pulse Code Modulation

Remote detection acoustic logging has huge amount of data, which brings a great challenge to upload all data in real time for cable and conduct fast logging. In order to solve the problem of real-time transmission of remote detection acoustic logging, a downhole logging data compression algorithm based on differential non-uniform quantization and adaptive coding was proposed after analyzing the characteristics of the full waveform data of remote detection acoustic logging. The hardware system, downhole compression software, and ground decompression software were designed to implement this algorithm. The basic and expansion performance of the algorithm were tested using water experiment data and borehole logging data. The results show that the compression rate of the algorithm is approximately 50%, and the distortions of the full waveform, as well as those in the first-peak region of the direct wave and the reflected wave, are all within 3%. The execution time and required operational storage space of the algorithm can meet the requirements of fast acquisition and real-time transmission. In addition, this algorithm has good adaptability and stability under different hardware and software environments and data characteristics. The results also indicate that the proposed algorithm can compress the remote detection acoustic logging data, improving the cable transmission rate and remote detection acoustic logging speed.