Melut盆地富含CO_(2)油气藏的成因及期次  

Genetic Origin of CO_(2)-Rich Oil Reservoirs and Pool-Forming Period in Melut Basin, Southern Sudan

作　　者：李威 窦立荣 文志刚[2] 张光亚 程顶胜[3] Li Wei;Dou Lirong;Wen Zhigang;Zhang Guangya;Cheng Dingsheng(CNOOC Research Institute Co.Ltd.,Beijing 100028,China;College of Resources and Environment,Key Laboratory of Exploration Technologies for Oil and Gas Resources of the Ministry of Education,Yangtze University,Wuhan 430100,China;Research Institute of Petroleum Exploration&Development,PetroChina,Beijing 100083,China)

机构地区：[1]中海油研究总院,北京100028 [2]长江大学资源与环境学院,油气资源与勘探技术教育部重点实验室,湖北武汉430100 [3]中国石油勘探开发研究院,北京100083

出　　处：《地球科学》2022年第4期1459-1469,共11页Earth Science

基　　金：国家油气重大专项项目(No.2011ZX05029);中国石油天然气股份有限公司科技专项(No.2013D-0902)。

摘　　要：Palogue油田的发现打开了Melut盆地古近系勘探新方向,证实了北部凹陷为富油气凹陷.Palogue油田具有以下白垩统为主力烃源岩,古近系为主力成藏组合的跨时代运聚风格,幔源CO_(2)气体对油气的聚集和改造具有不可忽略的作用.通过对CO_(2)气体、原油特征、生标特征、包裹体特征进行研究,结合地层埋藏史,分析油气特征及成藏期次.结果表明:Palogue油田具有两期成藏的特征,古近纪中期发生第1期油气成藏事件,随后原油被降解;古近纪晚期-新近纪以来,伴随幔源CO_(2)气体油气发生第2次运移充注事件,且CO_(2)气体对油藏进行了强烈的气洗作用.The oil discovery in the Paleogene of Palogue oilfield of the Melut basin is a milestone in the potentiality of new exploration play direction,it confirmed that the northern sag is hydrocarbon⁃rich sags.The Lower Cretaceous source rock is the major source rock of Melut basin,the Paleogene is its main seal reservoir assemblage.The formation mechanism and model of oil and gas accumulated were proposed based on the specific tectonic-stratigraphic assemblages and evolution history of the Melut basin.Oil and gas accumulation were influenced by mantle CO_(2).Analyzed characteristics of oil and hydrocarbon accumulation were investigated using a suite of burial history,fluid inclusions,CO_(2) and crude biomarker characteristics by taking Palogue oil reservoir as an example.The results show that the Palogue oil reservoir has experienced two episodes of hydrocarbon accumulations,the first episodes of the hydrocarbon accumulation happened in the Middle Paleogene,but the crude oil was strongly biodegraded.Since the Late Paleogene to Neogene,the second episodes of hydrocarbon accumulations accompany by mantle CO_(2).The oil and gas enter traps to form the anticlina reservoirs,CO_(2) under the gravity differentiation has carried on the intense gas washing effect to reservoir.

关 键 词：Melut盆地 PALOGUE油田 成藏过程 蒸发分馏作用 南苏丹 石油地质 

分 类 号：P618[天文地球—矿床学] TE122[天文地球—地质学]