姬塬地区长4+5致密油藏油水分布影响因素分析

FACTORS INFLUENCING THE OIL-WATER DISTRIBUTION OF CHANG 4+5 TIGHT RESERVOIR IN JIYUAN AREA

鄂尔多斯盆地姬塬地区长4+5储层致密,为典型的低渗透储层,在油藏大面积发育的同时,层间和层内含油性差异较大,油水关系复杂,油水分布影响因素待进一步明确。在储层及油藏基本特征研究的基础上,从源储配置关系、储层非均质性等方面开展油水分布影响因素分析,表明:三叠系延长组长7广富分布的烃源岩与差异成岩作用形成的长4+5优质储层能够形成良好的源储配置,油气经裂缝等运移通道,在三角洲前缘砂体中大面积、大规模聚集成藏;受烃源岩厚度差异的影响,研究区东、西各区带成藏充注动力不等,含油饱和度不同;储层非均质性影响石油局部富集程度,水下分流河道主砂带排驱压力较低、中值压力较低,是油藏的主要富集场所。

The chang 4+5 reservoir in Jiyuan area of Ordos basin is typical low permeability reservoir. Althoughit develops a lot of oil reservoir,the difference between interlamination and interior of layer is large,which leadsto a complex distribution of oil and water. Through analysis of this factors we can reach the following conclusions.Firstly,The chang 7 source rocks which distribute in a large area and the chang 4+5 reservoir controlled by thedifferences of diagenesis can form a good combination. The Oil can accumulate from source rock to the delta frontsandstone through fracture massively. Secondly,The accumulation dynamics in different zones of the study areaare different,which is affected by the thickness of the source rocks. Because the enrichment degree of oil is af-fected by the anisotropism of reservoir,the major sand of the underwater distributary channel is the main positionof accumulation where the displacement pressure and the median pressure are lower.