牛庄洼陷沙三中亚段浊积岩储层特征及油气富集规律

综合利用钻井岩心、测录井、试油等资料,通过岩心观察、薄片鉴定、物性测试、流体包裹体分析等技术方法,对牛庄洼陷沙三中亚段浊积岩储层特征、油气分布特征进行研究,总结油气富集规律。牛庄洼陷沙三中亚段浊积岩储层主要为岩屑质长石砂岩,以细砂岩为主,主要发育中高孔低渗特低渗透储层,储集空间类型以原生孔隙为主,次生孔隙较发育;压实作用中等,碳酸盐胶结为主,硅质胶结较发育,长石溶蚀最为常见。储层含油性与物性之间没有明显的对应关系,而是受埋深、地层压力和储层物性的综合控制。平面上油层围绕生烃中心和油源断层呈环带式分布,地层压力高值区与油源断层发育区是油气富集的有利场所。油气富集受烃源岩与储层的空间配置和烃源岩热演化与储层物性演化时间上的配置决定,不同埋深浅部储层不含油,深部储层易含油;相同埋深低物性储层不含油,高物性储层易含油;断层和地层超压发育区储层易含油。

Characteristics and oil and gas enrichment pattern of turbidite reservoir in the middle of third member of the Shahejie formation in Niuzhuang sub-sag

The characteristics of turbidite reservoir and oil and gas distribution and enrichment pattern in the middle of third member Shahejie formation in Niuzhuang sub-sag have been investigated through core observation, thin section identification, property test and fluid inclusion analysis using drilling core, logging and oil testing data. The turbidite reservoirs in the study area are mainly lithic arkoses, containing fine sandstone, with middle-high porosity and low permeability. The space types in the reservoir are mainly primary pores, and secondary pores also develop, with moderate compaction dominated by carbonate cementation and siliceous cementation in the secondary place, and feldspar dissolution is the most common dissolution. The oil content has no apparent corresponding relationships with physical properties of the reservoir, but is controlled comprehensively by buried depth, formation pressure and physical properties of the reservoir. In plane, oil layers have a ring type distribution around hydrocarbon generation center and oil source fault, and areas with high formation pressure and oil source fault development are the favorable places for oil and gas enrichment. Oil and gas accumulation is determined by the spatial allocation relationship of hydrocarbon source rocks and reservoirs, and the timing allocation relationship of thermal evolution of hydrocarbon source rock and physical evolution of the reservoir. Reservoirs of shallow buried depth are oil-free, whereas those in deep areas tend to be oily. Reservoirs of similar buried depth tend to be oil-free in areas with poor physical properties and oil-rich in areas with good physical properties, and oil is likely to accumulate in fault-abundant and overpressured formation areas.