天然气水合物地层剪切模量参数岩石物理计算及叠前反演  

Rock physics calculation and pre-stack inversion of shear modulus parameters for natural gas hydrate-bearing sediments

作　　者：刘欣欣 王小杰 徐华宁[1,2] 杨睿 刘鸿 陈江欣 LIU Xinxin;WANG Xiaojie;XU Huaning;YANG Rui;LIU Hong;CHEN Jiangxin(Qingdao Institute of Marine Geology,China Geological Survey,Qingdao 266237,China;Laboratory for Marine Mineral Resource,Qingdao Marine Science and Technology Center,Qingdao 266237,China)

机构地区：[1]中国地质调查局青岛海洋地质研究所,青岛266237 [2]青岛海洋科技中心海洋矿产资源评价与探测技术功能实验室,青岛266237

出　　处：《海洋地质与第四纪地质》2024年第6期60-70,共11页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金“南海北部高富集天然气水合物储层特征与成藏控制机理研究”(U2244224),“西太平洋多圈层相互作用数据集成研究”(92358303);山东省自然科学基金“天然气水合物频变衰减特征定量研究”(ZR2022MD029),“跨频带融合天然气水合物储层检测研究”(ZR2021MD118)。

摘　　要：利用地震资料进行天然气水合物识别,需要解决两个重要问题,一是建立含天然气水合物地层的弹性参数与水合物物性参数之间的定量关系;二是建立地震叠前数据与弹性参数之间的定量关系。针对上述问题,本文从神狐海域天然气水合物的微观赋存形态出发,重点考虑水合物的非零剪切模量特征,利用非耦合微分有效介质(DEM)理论、斑块饱和理论进行岩石物理建模,建立了天然气水合物饱和度与弹性参数之间的非线性关系,并通过弹性参数的敏感性分析以及交会分析,确定了剪切模量对水合物含量有较好的指示作用;使用叠前贝叶斯地震反演方法,从叠前地震数据中提取水合物剪切模量参数,结果与SH2站位测井数据有较好的一致性,有效地进行了天然气水合物识别。本方法可为海域天然气水合物识别和预测提供有力的技术支持。To accurately estimate gas hydrate content using seismic data,two key problems are needed to be solved:the first is to establish the quantitative relationship between the elastic parameters and physical parameters of hydrate-bearing sediments;the second is to establish the quantitative relationship between seismic pre-stack data and the elastic parameters.In view of the above problems,we combined the microscopic structure of gas hydrate-bearing sediments in Shenhu area on the focus of its characteristics of non-zero shear modulus,used the uncoupled differential effective medium(DEM)theory and patchy saturation theory to carry out the modeling of rock physics,and established the nonlinear relationship between gas hydrate saturation and elastic parameters.Through the analysis of sensitivity and crossplots of elastic parameters,we determined that the shear modulus is a good indicator to the hydrate content.Using the pre-stack Bayesian seismic inversion method,the shear modulus of hydrate-bearing sediments were extracted from the pre-stack seismic data,and the natural gas hydrate was effectively identified.The method in this study can provide a technical support for the identification and prediction of natural gas hydrate in sea areas.

关 键 词：天然气水合物 岩石物理 剪切模量 地震反演 

分 类 号：P736[天文地球—海洋地质]