基于连续小波变换的天然气水合物层地震数据多尺度分析——布莱克海台USGS95-1测线应用实例  

Multi-scale Study of Seismic Data from Sediments Containing Gas Hydrates Based on Continuous Wavelet Transform: A Case Study of Line USGS95-1 in Blake Ridge

作　　者：李敏锋[1] 李灿苹[1] 刘学伟[1] 杨丽[1] 

机构地区：[1]中国地质大学地球物理与信息技术学院,北京100083

出　　处：《现代地质》2006年第1期109-114,共6页Geoscience

基　　金：国家"863"计划项目(2001AA611020);国家重点基础研究发展规划项目(G20000467)

摘　　要：似海底反射(BSR)是目前天然气水合物层识别的主要依据,但是当BSR不明显或者缺失的时候怎样识别水合物层,以及水合物层顶面和下伏游离气层底面如何确定,仍然是水合物识别中难以圆满解决的两大难题。以布莱克海台USGS95-1测线地震数据为例利用小波变换进行多尺度研究发现水合物层和游离气层表现出不同的尺度特征:水合物层表现出大尺度特征,而游离气层具有小尺度特征;在最佳尺度剖面上,水合物层表现为低尺度背景中的近似平行于海底的高尺度带。利用水合物层和游离气层的这种尺度差异不但可以识别水合物层,而且还可以推断水合物层的顶面和游离气层的底面。Bottom simulating reflector （BSR） is the main indicator of gas hydrates. However, there are still two problems which are not successfully solved up to now in identification of gas hydrate： one is how to identify hydrate sediments when BSR is not clear or not in existence on seismic sections, and the other is how to recognize the top of the hydrate layer and the bottom of the free gas layer. In this paper, the seismic data of line USGS95-1 in Blake Ridge are studied through wavelet multi-scale method to show that wavelet scales of seismic data from hy- drate sediments are larger than the ones of the data from free gas layer. Moreover, the gas hydrate layer on optimal-scale section shows a high scale zone of paralleling bottom in the low scale background. This difference in wavelet scales of seismic data between gas hydrate sediments and free gas area can be used not only to recognize gas hydrates, but also to distinguish the top of the hydrate layer and the bottom of the free gas layer.

关 键 词：天然气水合物 小波变换 似海底反射 最佳尺度 游离气 布莱克海台 

分 类 号：P631.4[天文地球—地质矿产勘探]