南海北部神狐海域天然气水合物成藏系统  

Natural gas hydrate accumulation system in the Shenhu sea area of the northern South China Sea

作　　者：苏丕波 梁金强[1,2,3] 张伟 刘坊[1,2,3] 王飞飞 李廷微 王笑雪 王力峰 SU Pibo;LIANG Jinqiang;ZHANG Wei;LIU Fang;WANG Feifei;LI Tingwei;WANG Xiaoxue;WANG Lifeng(Key Laboratory of marine Mineral Resources,Ministry of Natural Resources//Guangzhou Marine Geological Survey,China Geological Survey,Guangzhou,Guangdong 510075,China;Gas Hydrate Engineering Technology Center,China Geological Survey,Ministry of Natural Resources,Guangzhou,Guangdong 510075,China;Guangdong Laboratory of Southern Marine Seience and Engineering-Guangzhou,Guangzhou,Guangdong 510075,China)

机构地区：[1]自然资源部海底矿产资源重点实验室·中国地质调查局广州海洋地质调查局 [2]中国地质调查局天然气水合物工程技术中心 [3]南方海洋科学与工程广东省实验室(广州)

出　　处：《天然气工业》2020年第8期77-89,共13页Natural Gas Industry

基　　金：自然资源部中国地质调查局地质调查项目“神狐海域天然气水合物先导试验区资源评价”(编号:DD20190224)。

摘　　要：深化对于南海北部神狐海域天然气水合物(以下简称水合物)成藏系统的认识,有助于科学评价该区水合物资源潜力、指导下一步的勘查工作。为此,借鉴常规油气成藏系统理论,充分利用水合物勘查实践成果,提出了水合物成藏系统的概念,并以此系统论思想为基础,从水合物成藏的气源供给、流体输导及储集层出发,利用地震、测井、取心及测试等资料,深入分析了神狐海域水合物成藏系统的特征。研究结果表明:①该区水合物成藏具有双源、多通道、多期成藏的特征;②来自浅部的生物气和深部的热成因气,通过具有渗漏能力的断裂、底辟、气烟囱等通道以及具有一定渗透性的沉积岩运移至水合物稳定域内形成水合物藏;③气源供给、输导通道及储集层共同控制了水合物的差异聚集;④水合物成藏系统在纵向上呈现出明显的成藏组合,主要表现为低饱和度水合物层-高饱和度水合物层-水合物+游离气层-游离气层上下叠置分布的特征;⑤平面上,不同区域水合物的产出状态、分布厚度、饱和度等差异明显。结论认为,神狐海域具有良好的水合物成藏条件,但水合物在聚集和分布上则呈现出不均匀性的特征,评价其资源潜力应综合考虑气源供给、输导通道及不同类型储集层在时空下的耦合关系。Deepening the understanding of the natural gas hydrate(NGH)accumulation system in the Shenhu sea area of the northern South China Sea is conducive to scientifically evaluating the NGH resource potential and guide further exploration in this area.In this paper,the concept of NGH accumulation system was proposed based on theories of conventional hydrocarbon accumulation system,combined with practical exploration achievements.Then,based on this system theory,the characteristics of the NGH accumulation system in the Shenhu sea area were analyzed in terms of gas source supply,fluid migration and reservoir by using seismic,logging,coring and testing data.And the following research results were obtained.First,the NGH accumulation system in this area is characterized by dual-source,multi-pathway and multi-stage accumulation.Second,shallow biogenic gas and deep thermogenic gas migrate through percolating pathways(e.g.,fault,diaper and gas chimney)and permeable sedimentary rocks to the NGH stability zone to form NGH reservoirs.Third,differential NGH accumulation is under the joint control of gas source supply,migration pathway and reservoir.Fourth,there is vertically an obvious play in the NGH accumulation system,which presents the superimposed distribution characteristics of low saturation NGH layers,high saturation NGH layers,NGH&free gas layers,and free gas layers.Fifth,in the plane,NGH occurrence form,distribution thickness and saturation vary greatly in different areas.In conclusion,there are good conditions for NGH accumulation,but NGH accumulation and distribution is uneven,so the coupling relationship between gas source supply,migration pathway and reservoir in space and time shall be considered comprehensively when its resource potential is evaluated.

关 键 词：南海北部 神狐海域 天然气水合物成藏系统 气源供给 输导通道 储集层 资源潜力 

分 类 号：P618.13[天文地球—矿床学]