高邮凹陷马家嘴地区油气差异分布的影响因素分析

Analysis of the Influencing Factors of Differential Hydrocarbon Distribution in Majiazui Oilfield,Gaoyou Sag

根据现代油气成藏理论,从分析原油成因和油气分布规律出发,结合油源对比结果,对高邮凹陷马家嘴地区油气差异性分布的影响因素进行了分析。结果表明:马家嘴地区以断层-岩性油藏为主,主要沿真②断层和汉留断层分布有两类原油,均来自异地的邵伯次洼阜四段烃源岩,油气充注期都为始新世中、晚期;原油类型分带分布并非是不同源或同源不同运移期所致,而主要为运移路径不同所致;真②断层和汉留断层控制了油气主运移通道,且前者输导油气能力较强,造成了沿真②断层分布的油藏成熟度整体低于沿汉留断层分布的油藏;在沉积微相的控制作用下,离断层稍远的物性较好的扇中和扇端的含油性普遍好于靠近断层的物性较差的扇根;断层产状、砂体尖灭方向和地层走向的配置关系决定了断层-岩性油藏的充满度。

Based on the modem hydrocarbon accumulation theories, through analyzing causes for hydrocarbon accumulation and distribution characteristics, this paper analyzes factors that influence differential hydrocarbon distribution in the Majiazui area of Gaoyou Sag, Subei Basin. The results indicate that fault-lithologic reservoir is the main reservoir type which contains two kinds of hydrocarbons originatied from the Elf4 source rock in Shaobo sub-sag and hydrocarbon charging occurred in the middle-late stage of the Eocene. The zonal distribution of different hydrocarbons was caused by different migration pathways, not by different sources or different migration periods; Zhen（2） and Hanliu faults serve as the dominant migration pathways; Zhen（2） fault shows relatively stronger ability for hydrocarbon migration, thus hydrocarbon that occurred along Zhen（2） fault shows lower maturity than that along Hanliu fault. Under the influence of sedimentary microfacies on reservoir properties, reservoirs of middle-terminal fan far from faults show higher oil-bearing properties than those of root-fan near faults; the degree to which fault-lithologic traps are filled is determined by matching fault orientations, sand beds pinching-out directions, and strike of strata.