薄互储集层对声波全波列测井波形的影响

The influence of thin interbedded-reservoir upon the waveform of acoustic all-wave train logging

针对孔隙薄互层模型进行产压—速度有限差分数值模拟，发现层界面、低速薄夹层、高速薄夹层、薄互层及裂缝对声波全波列波形显示出以下特征：各组分波在任意分层界面处都会产生反射液，其中低频斯通利波的反射最为突出；当薄层厚度大于0．2m时，在上、下层界面处会出现两组反射液，利用反射波信息可分辨出薄层厚度，评价其储集特性；当薄层厚度小于0．1m时，两级反射波逐渐重叠变为一组反射波，反射波能量也逐渐减弱，并与井外存在裂缝时的波形特征相似。

Having made the finite-difference numerical modeling of acoustic pressure versus velocity by using porous thin interbed model, we found that horizon interface,low-velocity thin interbed, high-velocity thin interbed, thin interbeds and fractures produce following responses in acoustic all-wave train logging:. Each component wave group brings reflection waves at any interface, of which the reflection wave due to low-frequency Stoneley wave is most highlighted one.. When a thin interbed is thicker than 0. 2m, the upper and down interfaces generate two groups of reflection waves, by which both the bed thickness and reservoir characteristic may be known.. When a thin interbed is thinner than 0. 1m, two groups of reflection waves merge into one, reflection energy weakens, and their waveforms are similar to those which appear in the case of fractures existing outside a borehole.