摘要
渤海湾盆地渤中凹陷渤中21⁃22构造区CO_(2)含量高,对油气成藏具有深刻影响,但相关研究薄弱。基于天然气组分、碳同位素和氦同位素等地球化学资料,对渤中21⁃22构造区CO_(2)与烃类气成因、CO_(2)与油气成藏关系及其对油气成藏的影响进行了深入分析。结果表明:渤中21⁃22构造区烃类气与非烃气含量大致相当,CO_(2)为火山幔源无机成因,烃类气主要为沙河街组三段的偏腐殖型干酪根热解气。CO_(2)主充注期为新近系馆陶组沉积时的火山岩浆活动期,油气的主成藏期为新近系明化镇组沉积期以来,CO_(2)充注成藏期明显早于原油和烃类气。渤中21⁃22构造区为早期CO_(2)充注、后期油气成藏的模式,早期充注的CO_(2)会优先占据有效储集空间,阻碍后期原油和烃类气的持续充注成藏,仅部分烃类气可继续充注并与CO_(2)混合,形成现今的高含CO_(2)气藏。
The high CO_(2) content have profound impacts on oil and gas accumulation in Bozhong 21-22 structure,Bohai Bay Basin.And,but the relevant research is weak.Based on the geochemical data of natural gas components,carbon isotopes and helium isotopes,the genesis of CO_(2) and hydrocarbon gas is revealed.The relationship between CO_(2) and hydrocarbon accumulation and its influence on hydrocarbon accumulation in Bozhong 21-22 structure area are analyzed.The results show that the content of hydrocarbon gas and non-hydrocarbon gas in Bozhong 21-22 structural area is approximately the same.The CO_(2) is the volcanic mantle-derived inorganic origin,and the hydrocarbon gas is mainly the partial humic kerogen pyrolysis gas from the third member of Shahejie Formation.The main charging period of CO_(2) was the volcano-magmatic period during the deposition of the Guantao Formation in the Neogene.The main accumulation period of oil and gas was the Minghuazhen Formation in the Neogene,and the charging and accumulation period of CO_(2) was obviously prior to that of hydrocarbon.The accumulation model of the Bozhong 21-22 structural area is firstly charged by CO_(2),subsequently by hydrocarbons.The early-charging CO_(2) will infill the effective storage space first and inhibit the continuous filling and accumulation of late crude oil and hydrocarbon gas.Only part of hydrocarbon gas can continue to fill and mix with CO_(2) to form the present-day high-CO_(2) gas reservoir.
作者
胡安文
王飞龙
王广源
万琳
张鑫
HU Anwen;WANG Feilong;WANG Guangyuan;WAN Lin;ZHANG Xin(Bohai Oil Research Institute,Tianjin Branch of CNOOC Limited,Tianjin 300459,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第12期2151-2159,共9页
Natural Gas Geoscience
基金
中海石油(中国)有限公司重大科技专项(编号:CNOOC-KJ135ZDXM36TJ08TJ)
中国海洋石油有限公司“十四五”重大科技项目(编号:KJGG2022-0302)联合资助.
