束鹿凹陷古近系油气成藏模式与主控因素

The Paleogene Hydrocarbon Accumulation Pattern and Main Controlling Factors in Shulu Sag

在综合分析石油地质基本条件、油气分布以及预测油气优势运移通道的基础上,明确了束鹿凹陷古近系油气富集的主控因素。鼻状构造与断裂系统的交叉有利于圈闭形成,西斜坡内带的鼻状构造翼部易形成构造-岩性复合油气藏;断层连通性及生储盖组合控制油气的运移方式,古近系深层以平面侧向运移为主,浅层以断层的油气垂向运移为主,由此可建立深层侧向运聚、浅层垂向运聚等2种成藏模式;构造格局、岩相组合与油气源的空间配置控制油气分配,依据油气运移网络、储盖组合划分的成藏组合和成藏带中,成熟烃源岩体积与探明储量具有良好的正相关关系。综合评价认为,束鹿凹陷古近系以南洼槽周缘地区、西曹固西斜坡中段为岩性、地层圈闭,是油气藏的有利勘探区带。

The main control factors of oil and gas enrichment were determined in Shulu Sag based on comprehensive analysis of petroleum geological conditions,oil distribution and the prediction of advantage oil migration channel.The cross of nose structure and fracture system were favorable for trap formation,structural-lithologic reservoir was formed in the nose structure wing of inner zone of west slope.The migration of oil and gas was controlled by fault connectivity and source-reservoir-cap assemblage.The plane lateral migration was dominated in the deep system of Paleogene and vertical oil migration of fault was dominated in the shallow system.Two kinds of petroleum accumulation modes could be set up such as lateral migration of deep formation and vertical migration of shallow formation.The oil and gas distribution was controlled by spatial configuration of structural framework,lithofacies assemblages and source of oil and gas.On the basis of petroleum migration network and reservoir-cap assemblage,The division of accumulation assemblages and belt was accomplished,in which good positive correlation was displayed between mature source rock volume and proven reserves.Comprehensive evaluation of Paleogene in Shulu Sag shows that the favorable exploration zones of lithologic-stratigraphic reservoir are located in such areas as the peripheral region of south subsag and middle part of western slope in Xicaugu Area.