纵波AVO、转换横波信息在浅层气检测中的应用

Applying the AVO information of P-wave and converted shear wave to shallow gas detection

东部地区,浅层气藏一般呈亮点反射特征。由于叠加对振幅的影响,给使用亮点技术检测油气带来困难。本文提出用AVO纵波信息代替常规叠加剖面,并结合转换横波信息来检测浅层亮点气。文中给出了从常规地震资料中提取自激自收纵波、转换横波的方法及其相对波阻抗反演方法,并以一浅层气藏的检测为例,说明该方法有良好的应用效果。

In the east part of China,shallow gas reservoir ususlly produces bright spot reflection in seismic section. Data stacking affects amplitudes, which makes it difficult to use bright spot technique in gas detection. The bright spot due to shallow gas reservoir can be determined by analysing AVO information of P-wave and converted shear wave, instead of conventional stacked section. A method is given of deriving zero-offset longitudinal and converted shear waves from conventional seismic data. A way of making relative wave impedance inversion is also described. Excellent feasibility of this method is shown by an example of a shallow gas reservoir detection.