鄂尔多斯盆地是一个大型中生代内陆坳陷型盆地 ,油气资源丰富。主力含油层系三叠系延 长组发育一套湖泊 —三角洲相沉积 ,油藏为典型的岩性油藏 ,储集条件较差 ,储层非均质性强。油 藏的形成主要受优质烃源岩、 有利储集砂体的控制 ,后期建设性的成岩作用及构造作用对储层的改 善具有重要的意义 ,长 7 过剩压力为油气运聚的主要动力 ,受沉积环境、 储层特征、 烃源条件和储盖 组合等方面的影响 ,主要发育东北曲流河和西南辫状河 2 种三角洲沉积模式 ,三角洲前缘水下分流 河道和河口坝是延长组油藏形成的最为有利的沉积相带。

Ordos Basin is a large Mesozoic inland depressed basin with rich oil and gas resources. Triassic Yanchang Formation is the main oil-bearing formation , where a set of lacustrine-delta facies deposits is developed. The reservoir is a typical lithologic reservoir with poor reservoir conditions and high reservoir heterogeneity. The forming of the reservoir is mainly under the control of high quality of source rocks and favorable reservoir sand bodies. The late constructive diageneses and tectonisms are closely related to the improvement of the reservoir. The overpressure of Chang 7 is the main driving force for the hydrocarbon migration and accumulation. Effected by the aspects of depositional environment , reservoir features , source rocks and the combination of the reservoir and seal , NE meandering river and SW braided river delta depositional patterns are developed. The delta front subsea distributary channel and mouth bar are the most favorable sedimentary facies belt for the generation of Yanchang Formation reservoirs.