随钻声波测井数据实时压缩算法

A REAL-TIME DATA COMPRESSION ALGORITHM FOR ACOUSTIC WAVE LOGGING WHILE DRILLING

针对随钻测井信号低传输速率特性,结合随钻声波测井时数据量大的实际,研究了波列数据实时在线压缩算法。在分析随钻声波测井信号特征的基础上,建立了基线和波形相结合的分段压缩模型,提出了预测编码与小波变换相结合的压缩方法。设计了符合基线变化的预测器来实现对预测值限幅后编码压缩,推导了与波形信号最佳匹配的小波函数,实现了基于提升算法的小波变换波形数据压缩,提高运算速度,满足实时性要求。通过对比原始信号及压缩恢复信号,验证了该算法能有效压缩信号,较好地保留信号波峰特征,并对信号中白噪声的消噪抑制具有很好的效果。

Confined to the hostile environment of logging while drilling,the data transportation rate is very low,a real-time and on-line data compression algorithm is researched to compress the huge acoustic wave logging data.The subsection compression model had been proposed according to the characteristic of acoustic logging while drilling,the combination of prediction code and wavelet transform is put on the data compression.In this paper,the special predictor for the variation of base-line and the optimal and wavelet matching to the acoustic wave signal is put forward.The encode compression and lifting-scheme algorithms are applied to compress the base-line and wave data respectively to satisfy the real-time requirement of system.Experiment proves that the algorithm can compress the acoustic wave data efficiently with the characteristic reserved and white noise restrained and eliminated.