基于小波包变换与近似熵的储集层识别

Reservoir Identification Based on Wavelet Packet Transform and Approximate Entropy

通常不同地层特征对应的地震波复杂程度均有差异。近似熵是一种反映信号复杂程度的特征量,对储层特征有一定反映。但是,地震波是有一定带宽的信号,在此带宽内,可能某一部分频段对油气层较为敏感,而其他频段的信号则对油气层的反应不够敏感,如果直接进行近似熵的计算,其结果往往不能很好地反映储层特征。鉴于这种情况,对小波包变换和近似熵结合进行储集层预测的方法进行研究,即对小波包分解的结果进行近似熵计算。实际资料计算结果表明,结合小波包分解和近似熵的储层识别方法,能够精确刻画储层形态。

In general complexities of seismic waveforms corresponding to different strata characters are different. Approximate entropy is a characteristic parameter reflecting signal complexity, which can reflect to some extent the characteristics of a reservoir. While there is a problem worthy of attention, seismic waves are signals with certain bandwidth within which some bands may be relatively more sensitive to the oil and gas reservoir, while others are not sensitive enough. Therefore, calculating the approximate entropy directly often leads to poor reflections of a res- ervoir. In view of this situation, the method based on wavelet packet transform and approximate entropy of reservoir identification are studied, namely use the results of wavelet packet decomposition to calculate approximate entropy. The computational result of actual data shows that the method based on wavelet packet transform and approximate entropy can be used to describe the reservoir accurately