Multicomponent seismic forward modeling of gas hydrates beneath the seafloor  

海底天然气水合物OBS多分量地震正演模拟（英文）

作　　者：杨佳佳[1] 何兵寿[1] 张建中[1] 

机构地区：[1]中国海洋大学海底科学与探测技术教育部重点实验室,青岛266100

出　　处：《Applied Geophysics》2014年第4期418-428,509,共12页应用地球物理（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.41174087,41204089);the National Oil and Gas Major Project(No.2011ZX05005-005)

摘　　要：We investigated the effect of microscopic distribution modes of hydrates in porous sediments, and the saturation of hydrates and free gas on the elastic properties of saturated sediments. We simulated the propagation of seismic waves in gas hydrate-bearing sediments beneath the seafloor, and obtained the common receiver gathers of compressional waves（P-waves） and shear waves（S-waves）. The numerical results suggest that the interface between sediments containing gas hydrates and free gas produces a large-amplitude bottomsimulating reflector. The analysis of multicomponent common receiver data suggests that ocean-bottom seismometers receive the converted waves of upgoing P- and S-waves, which increases the complexity of the wavefield record.根据Ecker的水合物沉积物的三种微观模式,计算含水合物沉积层和含游离气沉积物的弹性模量,分析对比了水合物的不同微观模式、不同水合物饱和度以及不同游离气饱和度对沉积物弹性模量的影响;从纵横波分离的弹性波动方程出发,采用交错网格空间有限差分方法模拟地震波在海底天然气水合物沉积地层的传播,得到纵、横波的海底地震(OBS)共接收点道集。数值算例表明,当水合物作为流体的一部分或胶结颗粒骨架时,仅纵波记录上存在BSR;当水合物胶结颗粒接触,纵、横波记录上均存在BSR。并且,OBS会接收到上行纵波和上行横波在海底界面形成的转换波,干扰横波记录上BSR的识别。

关 键 词：gas hydrates BSR finite difference forward modeling staggered grid 

分 类 号：P631.4[天文地球—地质矿产勘探]