不同类型盆缘区沉积体系展布与演化——以东营凹陷南坡博东潜山周缘地区为例

Distribution and evolution of sedimentary system in different types of basin edge: A case study of peripheral regions of Bodong Buried Hill,Dongying Sag

利用岩心、测井、录井和试油资料,系统研究了博东潜山周缘地区沙四段上亚段的沉积体系分布和油藏类型。结果表明:东部稳定型盆缘(广饶凸起)物源供给强,低位域时期主要发育三角洲沉积;西部活动性盆缘(博东潜山)缺乏物源供给,主要发育砂质滩坝沉积,且随着石村断层的翘倾,滩体沉积边界逐渐南移。湖侵域和高位域时期主要发育碳酸盐岩滩坝,活动性盆缘区滩体规模较小,但由于后期遭受风化淋滤储层物性较好。活动性盆缘的成藏较为复杂,勘探目标主要以早期地层油气藏、晚期构造岩性油气藏和碳酸盐岩岩性油气藏为主,而稳定型盆缘的圈闭类型相对单一,以早期的地层油气藏为主。

Based on core, logging, borehole and oil testing data, it was discussed in this paper the distribution of depositional systems and oil reservoir types in the upper subsection of the 4th member of the Shahejie Formation in the peripheral regions of the Bodong Buried Hill, the Dongying Sag. Due to strong source supply, delta sediments were widespread during the LST period in the eastern stable basin edge （the Guangrao Uplift）. In the western active basin edge （ the Bodong Buried Hill）, sandy beach bar sediments generated as the result of source shortcoming. Meanwhile, the sedimentary boundary of beach bar moved southwards with the lifting of the Shicun Fault. During the TST and HST periods, carbonate beach bar sediments were common, and the scale of carbon- ate beach bar in active basin edge decreased ; however, it had good physical properties because of weathering and leaching effects. The active basin edge has complex accumulation characteristics. Early stratigraphic reservoirs, late structural-lithologic reservoirs and carbonate lithologic reservoirs are the main exploration target. In the stable basin edge, only one trap type is found, indicating early stratigraphic reservoirs.