鄂尔多斯盆地伊陕斜坡延长组东、西成藏差异

Reservoir difference between east and west of Yanchang Formation in Yishan Slope,Ordos Basin

鄂尔多斯盆地伊陕斜坡延长组东、西部油藏分布格局存在较大差异,东部志靖—安塞地区纵向上油藏集中分布于长6段,平面上长6油层大面积连片分布;西部姬塬地区具有同一区块垂向上多油层叠合、平面上发育多个独立含油富集区的特点。分析认为,不同的运聚成藏模式导致了2个地区不同的油藏分布格局,主要表现在以下4个方面:①沉积规模不同。东部的志靖—安塞地区属于陕北复合三角洲的主体部分,沉积规模大于西部的姬塬地区。②储层物性差异较大。受沉积和成岩作用双重控制,志靖—安塞地区储层物性好于姬塬地区。③主要运移通道不同。志靖—安塞地区的主要运移通道是连通砂体,而姬塬地区主要是微裂缝。④运聚成藏模式不同。东部志靖—安塞地区为连通砂体侧向运移的运聚模式,西部姬塬地区为裂缝垂向多点式充注的运聚模式。明确盆地伊陕斜坡东、西成藏差异,总结石油运聚规律,对于指导盆地石油勘探部署及为勘探决策提供依据等,均具有重要的意义。

There is biggish difference in the reservoir distribution between the east and west of Yanchang Formation in Yishan Slope, Ordos Basin. In the eastern Zhijing-Ansai area, the reservoir mainly vertically distributed in Chang 6 Formation, and large area distribution in plane, while in the western Jiyuan area, multiple zones overlay in vertical and multiple rich zones developed in horizon in the same block. The analysis result shows that different migration and accumulation model cause the different reservoir distribution, which mainly displays in the following four aspects： ①Different sedimentary scale. It is the main body of Shanbei multiple delta in the eastern Zhijing-Ansai area, which is large than that in the western Jiyuan area. ②Different reservoir property under the dual control of deposition and diagenesis. The reservoir property in Zhijing-Ansai area is better than that in Jiyuan area. ③Different migration pathway. The main migration pathway in Zhijing-Ansai area is connected sand body, while it is micro-fracture in Jiyuan area. ④Different migration and accumulation model. It is connected sand body and parallel migration in the eastern Zhijing-Ansai area, while it is fracture and vertical multi-points migration in the western Jiyuan area. The reservoir difference between the east and west of Yishan Slope is defined and the migration and accumulation rule is summed up, which provides significant guidance for exploration and deployment.