地震流体识别方法在四川盆地页岩气“甜点”预测中的应用*

中国页岩气资源丰富, 但勘探水平相对较低。在钻井、测井资料匮乏的条件下, 高精度地震流体检测方法的研究至关重要。从地震弹性波方程入手导出了流体活动因子表达式, 该因子与储集层密度、黏度和渗透性成正比。将流体活动因子分析与高精度时频分析结合, 形成用于页岩气“甜点”预测的实用方法, 即首先基于高精度时频分析, 分析流体的时频特性, 计算出流体活动因子, 进而与测井资料结合量化页岩气“甜点”区流体活动因子的范围, 从而预测页岩气“甜点”分布区。该方法在四川盆地的应用表明, 其预测结果与钻井、测试结果吻合, 取得了良好的勘探效果, 对页岩气勘探具有重要的指导作用。

Application of|seismic liquid identification method in prediction of shale gas “sweet spots” in Sichuan Basin

The shale gas resource is abundant in China, but the exploration level is relatively low. High-precision liquid detection method based on seismic data is critical as there is few well data. Based on the seismic elastic wave equation, the liquid mobility factor formula is deduced and|the efficient exploration technique combined with high-precision time-frequency analysis algorithm is formed. The liquid mobility factor has a positive correlation with permeability, viscosity and density of reservoir. Based on the high-precision time-frequency analysis, the character of liquid is analysed, and the liquid mobility factor is calculated. Then, combined with well data, the range of factor in “sweet spot” area is guantified. The application in the Sichuan Basin demonstrates|the precision and efficiency of the method as the result is consistent with the test data of well. This method will play a significant guiding role in shale gas exploration.