基于运移输导体系的天然气水合物成藏类型——以琼东南盆地H区为例  

Accumulation of natural gas hydrate based on migrating system:a case study of H zone of Qiongdongnan Basin

作　　者：樊奇 李清平 吴涛 李丽霞 庞维新 朱振宇 FAN Qi;LI Qingping;WU Tao;LI Lixia;PANG Weixin;ZHU Zhenyu(CNOOC Research Institute Company Limited,Beijing 100028,China;State Key Laboratory of Natural Gas Hydrates,Beijing 100028,China;CNOOC Hainan Company,Haikou,Hainan 570100,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028 [2]天然气水合物国家重点实验室,北京100028 [3]中海石油(中国)有限公司海南分公司,海口570100

出　　处：《石油实验地质》2022年第2期262-269,共8页Petroleum Geology & Experiment

基　　金：国家重点研发计划(2016YFC030400,2019YFC0312301);国家自然科学基金(U19B2005);中国海油重点实验室自主前瞻基础研究课题(【2021】32号)联合资助。

摘　　要：琼东南盆地是南海天然气水合物富集区和重点勘查地区,但天然气水合物地质研究薄弱。通过三维地震资料解释、地球化学资料分析和大量调研统计,对琼东南盆地H区开展了以水合物成藏系统为主线、运移输导体系为重点的研究。累计48组地球化学数据分析表明,H区水合物分解气的甲烷碳同位素特征(δC_(1)=-48.2‰)和较高的乙烷、丙烷含量(C_(2+)含量为21%),指示该区气源具有“热成因气为主、含混合成因气”的特征。地震解释发现,H区第四纪构造活动程度弱,NNE走向发育的气烟囱构造群、多边形断裂—粉砂复合体、海底滑塌扇构成了主要运移输导体系和优质储层。基于H区天然气水合物的气源特征和运移输导体系,预测并分析了“富含热成因气的气烟囱型水合物、富含热成因气的多边形断裂—粉砂复合型水合物、富含热成因气和混合成因气的海底滑塌扇水合物”成藏类型。Gas hydrate is greatly developed in the Qiongdongnan Basin which is one of the key exploration targets in the South China Sea,but the geological study of gas hydrate is insufficient.With 3D seismic data interpretation,geochemical data analysis and a large number of investigations,a related research work of H zone in the Qiongdongnan Basin was carried out in this paper,with accumulation system as the main line and focused on migration and transportation system.According to the analysis of 48 sets of geochemical data,the hydrate decomposition gas in H zone has a methane carbon isotope value(δ^(13)C_(1))of-48.2‰and a higher content of ethane and propane(C_(2+)=21%),indicating that the gas is mainly thermogenic,and some are mixed gas.Seismic interpretation showed that the Quaternary tectonic activity in H zone was weak,and the NNE-trending gas chimney structure group,polygonal fault-silt complex and submarine slump body constituted the main migrating system and high-quality reservoir in the study area.Based on the gas source characteristics and migrating system of natural gas hydrate in H zone,three accumulation types were proposed,including the gas chimney type hydrate rich in thermogenic gas,the polygonal fracture-silt composite hydrate rich in thermogenic gas,and the submarine slump hydrate rich in thermogenic gas and mixed genetic gas.

关 键 词：气烟囱 多边形断裂 热成因气 天然气水合物 成藏 琼东南盆地 

分 类 号：TE132.2[石油与天然气工程—油气勘探]