鄂尔多斯盆地甘泉南部地区延长组长7致密油富集主控因素

针对鄂尔多斯盆地延长组长 7 油层组（简称长 7 ）致密油富集主控因素研究程度低、认识不一致等问题，在调研致密砂岩油形成的主要控制因素及与油分布关系的基础上，利用测井、录井、试油试采、分析测试等资料，对鄂尔多斯盆地甘泉南部地区长 7 致密油富集主控因素进行了总结。 结果表明：烃源岩、源储配置关系、沉积相、物性条件等均为鄂尔多斯盆地甘泉南部地区长 7 致密油富集的主控因素；广泛发育的长 7 ₃ 油层亚组（简称长 7 ₃ ）优质油源岩是长 7 中上部致密油形成的有利条件，控制着各层致密油发育的总厚度和分布范围；长 7 良好的源储配置关系为长 7 ₃ 生成的油能及时排出奠定了基础；优势相区控制着长 7 致密油的分布范围；致密砂、泥岩体遮挡下的相对高孔、高渗砂体控制着长 7 致密油的聚集部位。 该研究成果可为鄂尔多斯盆地延长组长 7 致密油乃至延长组其他类似特征致密油勘探起到一定的指导作用。

Main controlling factors of the enrichment of Chang7 tightoil of Yanchang Formationin southern Ganquan area,Ordos Basin

Based on the analyses of the main controlling factors for tight oil formation and its relationship with hydrocarbon distribution, the data of well logging, mud logging, well test and production test, laboratory analysis and test were used to study the main controlling factors of the enrichment of Chang 7 tight oil of Yanchang Formation in the southern Ganquan area, Ordos Basin. The results show that source rocks, source-reservoir assemblage, sedimentary facies and physical properties are the main controlling factors of the enrichment of Chang 7 tight oil in Ordos Basin.The widely developed high-quality source rocks in Chang 7 ₃ subzone are an important foundation for tight oil formationin the middle and upper layer of Chang 7, and control the total depth and scope of tight oil in each layer. Good source-reservoir assemblages ensure that the oil generated from the source rocks in Chang 7 ₃ subzone can expel and migrateinto the Chang 7 ₂ reservoir along the contact surfaces of sourcereservoir between Chang 7 ₃ subzone and Chang 7 ₂ subzone. Favorable sedimentary facies zones control the distribution of tight oil in Chang 7. The relatively high porosity and high permeability sand bodies sealed by tight sandstone and mudstone control the accumulation of tight oil in Chang 7. This study may play a guiding role for the exploration of Chang 7 tight oil in Ordos Basin.