莺歌海盆地乐东10区新近系黄流组储层天然气充注与超压演化史  

Gas charging and overpressure evolution history of the Neogene Huangliu Formation reservoir in Ledong 10 area,Yinggehai Basin

作　　者：范彩伟 刘爱群 吴云鹏 侯静娴 Fan Caiwei;Liu Aiqun;Wu Yunpeng;Hou Jingxian(Zhanjiang Branch of CNOOC Ltd.,Zhanjiang,Guangdong 524057,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《石油与天然气地质》2022年第6期1370-1381,共12页Oil & Gas Geology

摘　　要：莺歌海盆地乐东10区新近系黄流组储层异常高压极其发育,压力系数最高可达2.3,超压的发育和演化与天然气成藏关系密切。基于流体包裹体岩相学观察,通过流体包裹体显微测温和激光拉曼光谱分析恢复黄流组储层气包裹体捕获压力,研究储层天然气充注和压力演化的关系。莺歌海盆地乐东10区黄流组储层发育纯CO_(2)气包裹体、富CH_(4)气包裹体、CO_(2)-CH_(4)混合气包裹体,对应两期CO_(2)和两期烃类气体充注。两期CO_(2)充注时间分别在2.0 Ma和1.0 Ma,包裹体中碳同位素显示两期CO_(2)为无机成因。两期烃类气体充注时间均晚于两期CO_(2)充注时间,分别是在1.8 Ma和0.4 Ma。黄流组储层超压经历了先增后降的过程。在2.0~1.0 Ma,两期CO_(2)和一期天然气的充注使黄流组储层压力逐渐升高,第二期CO_(2)充注到黄流组储层中之后,最大压力系数达到2.43。第二期烃类气体充注对应的黄流组储层剩余压力和压力系数都低于第二期CO_(2)充注时期,可能指示了在第二期CO_(2)充注之后,存在天然气泄漏的现象,使储层压力在1.0~0.4 Ma降低。莺歌海盆地乐东10区黄流组储层天然气充注与压力演化的关系对认识天然气成藏规律具有重要意义。The abnormal high pressure of the Huangliu Formation reservoir in the Yinggehai Basin is quite common with a pressure coefficient reaching up to 2.3.The development and evolution of overpressure are closely related to natural gas accumulation.This study focuses on the relationship between gas accumulation and reservoir pressure evolution,based on the petrographic observation of fluid inclusions,coupled with the trapping pressure of gas inclusions in the Huangliu Formation reservoir revealed by microscopic temperature measurement of fluid inclusions and Laser Raman spectrometry.The reservoir of Huangliu Formation in Ledong 10 area of Yinggehai Basin develops pure-CO_(2) gas inclusions,CH_(4)-rich gas inclusions,as well as mixed CO_(2) and CH_(4) gas inclusions,corresponding to CO_(2) and hydrocarbon gas charging of two stages respectively.The two-stage CO_(2) charging occurred 2.0 Ma and 1.0 Ma ago from now,respectively,and the CO_(2) is of inorganic origin as shown by the carbon isotopes in the inclusions.The two-stage hydrocarbon gas charging occurred 1.8 Ma and 0.4 Ma ago from now,later compared with the CO_(2) charging.The overpressure of Huangliu Formation reservoir experienced a process of increasing first and then decreasing.From 2.0 Ma to 1.0 Ma,the two-stage CO_(2) and one-stage natural gas charging gradually increased the reservoir pressure of the study area.As the second-stage CO_(2) charging occurred in the formation,the maximum pressure coefficient reached 2.43.The residual pressure and pressure coefficient in the reservoir during the second-stage hydrocarbon gas charging are lower than the second-stage CO_(2) charging,which may indicate that natural gas leak might happen after the secondstage CO_(2) charging,which functions to reduce the reservoir pressure around 1.0 Ma to 0.4 Ma.The relationship between natural gas charging and pressure evolution of the Huangliu Formation reservoir in Ledong 10 area of Yinggehai Basin is of great significance to understanding the pattern of natural gas accumulation.

关 键 词：流体包裹体 拉曼光谱 古压力恢复 天然气充注史 黄流组 新近系 莺歌海盆地 

分 类 号：TE122.3[石油与天然气工程—油气勘探]