琼东南盆地天然气水合物地震识别与饱和度预测  

Seismic Identification and Saturation Prediction of Natural Gas Hydrate in the Qiongdongnan Basin

作　　者：邓勇[1,2] Deng Yong(School of Geophysics,China University of Petroleum(Beijing),Beijing 102249,China;Hainan Branch Company,China National Offshore Oil Corporation,Haikou 570100,China)

机构地区：[1]中国石油大学(北京)地球物理学院,北京102249 [2]中海石油(中国)有限公司海南分公司,海南海口570100

出　　处：《地球科学》2024年第5期1865-1875,共11页Earth Science

摘　　要：琼东南盆地是我国新发现的天然气水合物勘探靶区,主要发育孔隙型水合物和烟囱型水合物,两者在地震上表现出不同的反射特征,仅利用地震似海底反射(BSR)识别琼东南盆地深水区天然气水合物存在局限性.为成功实现琼东南盆地天然气水合物识别与饱和度预测,利用三维地震数据和钻井资料,开展了AVO正演和宽频地震反演分析,明确了天然气水合物弹性参数特征,建立了天然气水合物地球物理识别方法.在此基础上,针对孔隙型和烟囱型两种不同类型的水合物,分别建立各向同性和各向异性饱和度评价方法,利用有效介质理论实现水合物饱和度定量评价.基于高品质地震资料开展的宽频地震反演和饱和度预测研究,实现了琼东南盆地孔隙型水合物和烟囱型水合物识别,并圈定了天然气水合物富集区,优选出了3个最大饱和度在50%以上水合物矿藏,预测结果得到实际钻探的验证.本次研究成果对琼东南盆地水合物钻探站位选取以及降低水合物钻探风险具有指导意义,其研究方法对于其他类似盆地水合物勘探具有借鉴价值.Qiongdongnan basin is a newly discovered gas hydrate exploration target area in China.There are two types of gas hydrate(i.e.pore hydrate and chimney hydrate),which are characterized by different seismic reflection characteristics.However,there are limitations in using bottom simulating reflections(BSR)in seismic profiles to identify gas hydrate in deep water area of Qiongdongnan basin.For the identification and saturation prediction of gas hydrate in Qiongdongnan basin,AVO forward modeling and broadband seismic inversion analysis are carried out in this study.The elastic parameter characteristics of natural gas hydrate were clarified,and geophysical identification methods for gas hydrate were established.Then,isotropic and anisotropy quantitative saturation evaluation methods were established for pore and chimney hydrates respectively.Based on broadband seismic inversion and saturation prediction using high quality seismic data,this study successfully identified pore hydrate and chimney hydrate in Qiongdongnan basin,and delineated gas hydrate enrichment areas.Three hydrate deposits with maximum saturation above 50%have been selected,the prediction effect of which is further confirmed by drilling exploration.Our results contribute to the selection of hydrate drilling stations and reduce the risk of hydrate drilling in Qiongdongnan basin,and the research method has guiding significance for hydrate exploration in other similar basins.

关 键 词：天然气水合物 地震反射特征 宽频地震 饱和度 富集区 油气地质 

分 类 号：P618[天文地球—矿床学]