天然气水合物储层弹性波最小二乘逆时偏移研究  

A study of elastic least-squares reverse time migration for gas hydrate reservoirs

作　　者：李金丽 曲英铭[3] 刘建勋 岳航羽 李培[1,2] 陈德元 

机构地区：[1]国家现代地质勘查工程技术研究中心,河北廊坊065000 [2]中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000 [3]中国石油大学(华东)地球科学与技术学院,山东青岛266580

出　　处：《物探与化探》2017年第6期1050-1059,共10页Geophysical and Geochemical Exploration

基　　金：国家高技术研究发展计划("863"计划)课题(2012AA061403);中国地质调查局地质调查项目(DD20160224);中央级公益性科研院所基本科研业务费专项基金资助项目(AS2017J11)

摘　　要：天然气水合物的弹性性质相比于周围岩层有明显的差异。传统声波成像方法采用声波近似,无法对其弹性性质进行准确地描述,弹性波偏移方法的成像结果分辨率低、中深部成像能量弱、振幅不均衡,存在低频噪声和采集脚印。为此,文中发展了一种弹性波最小二乘逆时偏移方法,在该方法中,推导了准确的弹性波最小二乘理论框架下的偏移算子和反偏移算子。为了提高计算效率并节省内存,引入了基于编码技术的混叠数据弹性波最小二乘方法,将多炮数据叠加为一个超道集,并采用编码技术压制串扰噪声。通过对两个含天然气水合物模型的试算验证了本文方法对天然气水合物储层成像的有效性及优越性。The elastic properties of gas hydrate are obviously different from those of the surrounding rocks.The traditional acoustic ima- ging method using acoustic approximation cannot accurately describe the elastic properties.The imaging results of elastic wave migration method have low resolution, weak energy in deep regions, imbalance amplitude, low frequency noise and acquisition footprint. For this reason ,the authors have developed an elastic least-squares inverse time migration method.In this method ,an accurate migration operator and demigration operator in the framework of the elastic least squares theory are derived.To improve the computation efficiency and save memory,the authors introduced the multisource elastic least-squares migration method based on encoding technique, in which multiple data are added into a supershot and the encoding technique is used to suppress the crosstalk.The effectiveness and superiority of the pro- posed method for gas hydrate reservoir imaging are verified by the simulation results of two gas hydrate models.

关 键 词：天然气水合物 弹性波 最小二乘逆时偏移 编码 

分 类 号：P631.4[天文地球—地质矿产勘探]