辽中南洼东二段油气分布特征与成藏期次

经过多年勘探,辽中南洼东营组东二段油气分布表现为显示好、厚度大、储量小的"贫化"特征,断层侧向封堵分析表明,圈闭有效性差导致东二段油气难以富集成藏。根据流体包裹体产状、储层含油包裹体丰度(GOI)值统计、显微荧光特征和显微测温分析,结合单井热演化史分析,辽中南洼东二段油气主要经历了两期充注成藏。第1期发生于明化镇组沉积早期,距今9.0～5.1Ma;第2期发生于明化镇组沉积晚期,距今4.0～1.3Ma。断裂活动性表明本区在明化镇组沉积中期(距今5.1Ma)经历一次强烈构造活动,导致东二段储层大部分与馆陶组对接,第1期形成的古油藏被破坏调整,形成了现今东二段油气"贫化"分布特征。辽中南洼油气沿断层向浅层运移并聚集成藏,新近系是油气富集层系。

Hydrocarbon distribution characteristics and accumulation period of second member of Dongying formation in the south of Liaozhong sag

After many years of exploration , the hydrocarbon distribution characteristics of the second member of Dongying formation appear in dilution phenomenon with good shows , thick thickness and small reserves in the south of Liaozhong sag.Based on the analysis of lateral sealing of faults , hydrocarbon is difficult to accumulate in huge scale because of the bad availability of traps.According to the occurrences of fluid inclusions , GOI value Statistics , the microscopic fluorescence characteristics and microthermometric statistics , combined with the buried history-geothermal evolution history of the wells , there are two periods of hydrocarbon accumulation in Dong 2 Member in the south of Liaozhong sag.The first period was nearly from9.0 Ma to 5.1 Ma , which occurred in the early of Minghuazhen stage.The second period was nearly from4.0 Ma to 1.3 Ma , which occurred in the end of Minghuazhen stage.Based on the analysis of fault activities , It had experienced a strong tectonic activity in 5.1 Ma ago which occurred in the middle of Minghuazhen stage. Therefore , paleo-reservoirs had been adjusted because of the much more juxtaposition between the Dong 2 member reservoir and the Guantao formation , and the hydrocarbon distribution of Dong 2 member was in dilution phenomenon. Hydrocarbon was migrated to the shallow strata along the faults and accumulated in huge scale.Therefore , the Neogene formation is the main oil-gas exploration strata in the south of Liaozhong sag.