琼东南盆地深水区天然气成因类型及气源探讨——以宝岛凹陷北坡BX-1构造陵水组为例  

Discussion on Genesis Types and Gas Sources of Natural Gas in Deep Water Area of Qiongdongnan Basin:Taking Lingshui Formation of BX-1 Structure on Northern Slope of Baodao Sag as an Example

作　　者：廖高龙 闫琢玉 李百强 郭艳琴 吴珍珍 LIAO Gaolong;YAN Zhuoyu;LI Baiqiang;GUO Yanqin;WU Zhenzhen(Hainan Branch,CNOOC(China)Ltd.,Haikou,Hainan 570100,China;Zhanjiang Engineering Technology Branch,CNOOC Energy Technology&Services Limited,Zhanjiang,Guangdong 524057,China;School of Earth and Environment,Anhui University of Science and Technology,Huainan,Anhui 232001,China;School of Earth Sciences and Engineering,Xi’an Shiyou University/Key Laboratory of Shaanxi Province for Petroleum Accumulation Geology,Xi’an,Shaanxi 710065,China)

机构地区：[1]中海石油(中国)有限公司海南分公司,海南海口570100 [2]中海油能源发展股份有限公司工程技术湛江分公司,广东湛江524057 [3]安徽理工大学地球与环境学院,安徽淮南232001 [4]西安石油大学地球科学与工程学院/陕西省油气成藏地质学重点实验室,陕西西安710065

出　　处：《西安石油大学学报（自然科学版）》2024年第6期21-28,50,共9页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家油气重大专项项目(2016ZX05046-002)。

摘　　要：琼东南盆地深水区是中国深水天然气勘探的主力区域,该区域拥有的丰富油气资源使得其具有重要的经济和战略意义。盆地宝岛凹陷北坡的天然气成因类型仍存在煤成气与油型气的争议,导致宝岛凹陷目前的天然气勘探方向并不明确。以宝岛凹陷北坡BX-1构造陵水组为研究对象,通过天然气组分、碳同位素以及流体包裹体分析等,综合判别天然气成因类型并探讨天然气来源。结果表明,宝岛凹陷BX-1构造陵水组天然气烷烃组分主要为甲烷,天然气干燥系数中等-高,为湿气和干气的混合气体,非烃气体以二氧化碳为主。天然气中烷烃气成因类型主要为油型气和混合成因气(油型气与煤成气的混合气体),为正常有机成因,其来源除了渐新统海相生气层外,还包括部分始新统原油充注后在高温环境中的原油热解气或裂解气。二氧化碳气体主要为无机幔源成因,气体来源可能与区内火山活动有关,并经深大断裂沟通运移所致。研究结果有助于厘清宝岛凹陷的天然气成因及来源,并为研究区陵水组下一步天然气勘探方向提供指导。The deep-water area of Qiongdongnan Basin is the major exploration field for deep-water natural gas in China.It is of important economic and strategic significance due to the abundant oil and gas resources in this area.There is still a dispute between coal-formed gas and oil-type gas in the genetic type of natural gas on the northern slope of Baodao Sag in the Qiongdongnan Basin,so the current natural gas exploration direction in Baodao Sag is not clear.Taking the Lingshui Formation of the BX-1 structure belt of the northern slope of Baodao Sag as the research object,and the genetic type and source of the natural gas were comprehensively discriminated and discussed through the analysis of natural gas components,carbon isotopes,and fluid inclusions.The results show that the alkane gas components of the natural gas is dominated by methane.The natural gas has a medium to high dryness coefficient and is a mixture of wet and dry gases.Non hydrocarbon gases are mainly carbon dioxide.The origin of the alkane gases is mainly oil-type gas and mixed origin gas(oil-type gas and coal-formed gas),which is a normal organic origin.They are not only from the marine gas reservoirs of the Oligocene,but also the pyrolysis gas or cracking gas of some Eocene crude oil in high-temperature environment.The carbon dioxide gas is mainly caused by inorganic mantle source,which may be related to the volcanic activity in the area and transported through deep and large faults.The research results are helpful to clarify the origin and source of the natural gas in Baodao Sag,and provide guidance for the next natural gas exploration direction of the Lingshui formation in the study area.

关 键 词：成因类型 天然气来源 陵水组 宝岛凹陷 琼东南盆地 

分 类 号：TE122.111[石油与天然气工程—油气勘探]