地震多参数约束下的真假BSR识别

地震勘探是探测海底天然气水合物的重要手段,利用地震资料的诸多特征可以较好地识别海底天然气水合物,尤其是在识别似海底反射(BSR)方面发挥着重要作用。由于多次波等特征与BSR有很多相似之处,如果辨别不当就很容易被误认为是BSR,将会得出错误的结论。以我国某海域实际资料为例,从研究BSR的地震特征出发,指明多次波、气泡效应等多种假BSR现象,提出了利用精细速度分析、AVO特征分析、多次波压制等多种地震参数约束以识别真假BSR,进而提高海洋地震勘探精度,为寻找更多的海底天然气水合物提供技术保障。

IDENTIFYING BSR BY SEISMIC MULTI-PARAMETER CONSTRAINTS

Seismic survey is an important mean for detection of gas hydrates on seabed. Many seismic attributes could be used to identify submarine gas hydrates, but the Bottom Simulating Reflector, or BSR in brief, remains the basic. However, the multiple waves are sometimes very similar to the BSR, and easy to be falsely treated as a BSR. The wrong conclusions based on these false BSR will mislead decision-making. Therefore, it is critical to distinguish the true BSR from the false ones. In this paper, we proposed some seismic criteria to identify the multiples and bubble effect so as to separate them from BSR. Taking an example from Chinese sea territory, we used an integrated approach of velocity analysis, AVO and multiplies suppression, and the accuracy of marine seismic exploration is upgraded as the result. It will provide technical support to more effective gas hydrate exploration.