珠江口盆地阳江东凹高含CO_(2)油气藏的类型、成因及成藏过程  

Types, genesis, and formation of CO_(2)-rich reservoirs in the Yangjiangdong Sag, Pearl River Mouth Basin

作　　者：马宁 熊万林 龙祖烈 朱俊章 温华华 杨兴业 汪晓萌 MA Ning;XIONG Wanlin;LONG Zulie;ZHU Junzhang;WEN Huahua;YANG Xingye;WANG Xiaomeng(Shenzhen Branch of CNOOC Ltd,Shenzhen 518067,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,深圳518067

出　　处：《海洋地质与第四纪地质》2023年第1期118-127,共10页Marine Geology & Quaternary Geology

基　　金：“南海大中型天然气田形成条件、勘探潜力与突破方向”之课题3“南海东部大中型天然气田勘探潜力与突破方向”。

摘　　要：通过对阳江东凹高含CO_(2)油气藏的流体组分组成、P-T相图、原油生物标志化合物、天然气组分及同位素、流体包裹体进行研究,分析了高含CO_(2)油气藏的类型、成因及成藏过程。结果表明,阳江东凹高含CO_(2)的油气藏分为3类:第一类为含CO_(2)溶解气的常规油藏,第二类为含CO_(2)溶解气的挥发性油藏,第三类为含溶解烃的CO_(2)气藏。油气藏中原油主要为浅湖-半深湖相及半深湖-深湖相烃源岩成熟阶段的产物,烃类气均为原油伴生气,CO_(2)属于幔源型无机成因气。EP20-A井原油的充注时期为12~10.7 Ma,CO_(2)充注时期为5.6~1.7 Ma。EP20-C井存在两期原油充注及两期CO_(2)充注,第一期原油充注时期为14~6 Ma,为主要充注期,第二期原油充注时期为4~0 Ma,第一期CO_(2)的充注时期为11~10 Ma,第二期CO_(2)的充注时期为5~1.5 Ma。根据CO_(2)充注强度的相对大小,分别形成了EP20-C井含溶解烃的CO_(2)气藏,EP20-A井含CO_(2)溶解气的挥发性油藏,EP20-B井含CO_(2)溶解气的常规油藏。By studying the composition of the fluid wells, P-T phase diagram, crude oil biomarkers, natural gas components, isotopes and fluid inclusions of high CO_(2)oil and gas reservoirs in the Yangjiangdong Sag, the types, genesis, and formation of CO_(2)-rich reservoirs were analyzed.Results show that the CO_(2)-rich reservoirs could be divided into three types: i.e., conventional reservoir with CO_(2)-dissolved gas, volatile reservoir with high CO_(2)dissolved gas, and CO_(2)gas reservoirs containing dissolved hydrocarbons. The crude oil in the reservoir is mainly originated from shallow–semi-deep lake facies and semi-deep–deep lake facies in the mature stage. The hydrocarbon gas is crude oil associated,and CO_(2)belongs to mantle-derived inorganic gas. The charging period in EP20-A well is 12~10.7 Ma, and that of CO_(2)is 5.6~1.7 Ma. Two stages of crude oil charging and two stages of CO_(2)charging in EP20-C well were recognized. The first stage of crude oil charging is 14~6 Ma,which is the main charging period;and the second stage is 4~0 Ma. The first stage of CO_(2)charging period is 11~10 Ma, and the second is5 ~1.5 Ma. The relative magnitude of CO_(2)charging intensity show that the CO_(2)gas reservoir containing dissolved hydrocarbon was formed in well EP20-C, volatile reservoir containing CO_(2)dissolved gas was formed in well EP20-A, and conventional reservoir containing CO_(2)dissolved gas was formed in well EP20-B.

关 键 词：高含CO_(2)油气藏 流体类型 油气成因 成藏过程 阳江东凹 

分 类 号：P744[天文地球—海洋科学]