随钻测井数据有损压缩算法改进探讨与应用  

Improvement and Application of Lossy Compression Algorithm for LWD Data

作　　者：宋山 赵小勇 付华才 连太炜 张正炳[1] 罗明璋[1] SONG Shan;ZHAO Xiaoyong;FU Huacai;LIAN Taiwei;ZHANG Zhengbing;LUO Mingzhang(School of Electronic Information and Electrical Engineering,Yangtze University,Jingzhou,Hubei 434023,China;CNPC Bohai Drilling Engineering Co.,Ltd.,Binhai,Tianjin 300280,China;CNPC Chuanqing Drilling Engineering Co.,Ltd.,Chuandong Drilling Company,Chongqing 401120,China;CNPC Chuanqing Drilling Engineering Co.,Ltd.,Drilling and Production Engineering Technology Research Institute,Guanghan,Sichuan 618300,China)

机构地区：[1]长江大学电子信息与电气工程学院 [2]中国石油集团渤海钻探工程有限公司 [3]中国石油川庆钻探工程有限公司川东钻探公司 [4]中国石油川庆钻探工程有限公司钻采工程技术研究院

出　　处：《钻采工艺》2023年第6期170-176,共7页Drilling & Production Technology

基　　金：国家自然科学基金“基于声电复合传感机理的锚杆锚固结构荷载监测与评估方法研究”(编号:51978079);湖北省高等学校优秀中青年科技创新团队计划项目“智能材料与结构健康监测”(编号:T2020007)。

摘　　要：常规随钻测井一般采取泥浆脉冲传输技术,泥浆脉冲传输技术数据传输速率受限于自身的编码、解码及算法方式,已经难以满足日益增长的钻井工程数据传输需求,而常用于随钻测井的差分脉冲编码调制算法主要存在两个方面的缺陷:当原始数据变化剧烈时,部分解码数据误差较大,导致该部分解码数据不可信;另外,其压缩倍数较低。由于数据压缩技术有助于在保持泥浆脉冲传输技术硬件不变和信号传输速率不变的情况下有效提高其数据等效传输速率,文章对差分脉冲编码调制做了改进,将非均匀量化与均方根传播梯度下降法相结合,有效减小了解码数据的误差,并利用Huffman编码对非均匀量化编码结果做进一步压缩来提高压缩倍数。经过生产测试,结果表明:本文算法对电阻率数据和伽马数据的等效传输速率达到1.588 bit/s和1.782 bit/s,高于差分脉冲编码调制算法的1.164 bit/s和1.163 bit/s,压缩倍数分别达到了2.73倍和3.06倍,高于差分脉冲编码调制的2.00倍。同时,解码数据与采集数据信噪比分别达到27.97 dB和26.62 dB,高于差分脉冲编码调制的23.66 dB和19.15 dB。由此可见,本文改进算法在有效提升了差分脉冲编码调制的压缩倍数的同时减小了解码数据误差,对于提高泥浆脉冲传输技术在同样硬件条件情况下的等效传输速率具有重要意义。Conventional LWD generally adopts the mud pulse transmission technology(MPT).The MPT data transmission rate is limited by its encoding,decoding,and algorithm methods,which has been unable to meet the increasing demand for data transmission in drilling engineering.The DPCM algorithm commonly used in LWD has two main deficiencies:when the original data changes significantly,some decoded data errors are large,resulting in large errors in a small number of decoded data which is unreliable;the compression ratio is low.Since data compression technology can help effectively improve the data equivalent transmission rate of MPT while maintaining the same hardware and signal transmission rate,this paper proposes an improvement to DPCM,proposing a data compression algorithm based on differential non-uniform quantization and flexible grouping of Huffman coding.By combining non-uniform quantization with RMSProp optimization method,the error of decoding data is effectively reduced.Moreover,Huffman coding is used to further compress the non-uniform quantization results to improve the compression ratio.The results of production testing show that the equivalent transmission rates of the proposed algorithm for resistivity data and gamma data are 1.588 bps and 1.782 bps,respectively,which are higher than those of the DPCM algorithm,which are 1.164 bps and 1.163 bps.The compression ratios are 2.73 times and 3.06 times,respectively,which are higher than those of DPCM,which are 2.00 times.At the same time,the signal-to-noise ratio of the decoded data and the collected data reaches 27.97 dB and 26.62 dB,respectively,which is higher than that of DPCM,which is 23.66 dB and 19.15 dB.It can be seen that the improved algorithm effectively improves the compression ratio of DPCM while reducing the decoded data error,which is of great significance for improving the equivalent transmission rate of MPT.

关 键 词：随钻测井 差分脉码调制 HUFFMAN编码 数据压缩 泥浆脉冲 均方根传播梯度下降法 

分 类 号：TE271[石油与天然气工程—油气井工程]