井下核磁共振测井数据压缩的实现

Implementation of NMR logging data compression while drillingZHANG

基于随钻核磁共振测井仪器井下带宽有限、传输速率较慢的问题,设计适用于井下仪器的压缩解压缩算法,利用联合编码的方法在FPGA(现场可编程门阵列)硬件的基础上对井下数据进行压缩。对所设计的压缩解压缩算法进行试验验证,在验证压缩解压缩算法各个模块的准确性的基础上,对整个压缩解压缩系统进行测试。结果表明,基于FPGA设计的数据压缩解压缩算法可行。该算法需要消耗的硬件逻辑资源相对较少、规律性较强,更有利于FPGA的开发设计,并且在保证失真率较小的条件下可以有相对较高的压缩比,保证了经过压缩的数据满足实时传输的需求。

This paper presents a compression and decompression algorithm designed for NMR logging while drilling tools,which have limited downhole bandwidth and slow transmission rate.The algorithm uses the joint coding method to compress the downhole data on the basis of FPGA hardware.Experimental verification was conducted on the designed compression and decompression algorithm.On the basis of verifying the accuracy of each module of the designed algorithm,the entire com-pression and decompression system was tested.The results show that the designed algorithm based on FPGA is feasible.The algorithm is resource-efficient and has strong regularity,making it conducive to the development and design of FPGA.Addi-tionally,it has both high compression ratio and low distortion rate,ensuring that the compressed data meets the needs of real-time transmission.