姬塬地区位于鄂尔多斯盆地南部, 在区域上处于鄂尔多斯盆地陕北斜坡、天环坳陷2 个构造单元之间。姬塬腹地勘探程度较低, 对长3 和长4+5 沉积体系、沉积相和储层的展布、圈闭的成藏、油气富集规律等问题有待进一步认识。该文以露头、岩心、测井曲线为基础, 通过对区内岩性特征、测井曲线形态及沉积微相特征进行分析, 认为姬塬地区延长组长3 和长4+5 油层组主要由三角洲沉积体系和湖泊沉积体系组成, 并进一步分为2 种亚相和5 种微相。根据长3 和长4+5 的沉积微相的展布及演化规律可以得出研究区的沉积模式。

Jiyuan area, in southern Ordos Basin, is located at the structure unit between Shanbei Slope and Tianhuan Depression. The exploratory degree is low here, thus, the study on depositional system, sedimentary facies, reservoir distribution, traps accumulation, and the hydrocarbon enrichment of the member 3 and 4+5 of Yanchang Formation is not enough. Based on the outcrop, core and well log data, the lithologic characteristics, well log form and sedimentary microfacies are analyzed. The result shows that the member 3 and 4+5 are mainly composed of delta and lacustrine depositional systems, which can be further divided into two subfacies and five microfacies. According to the distribution and evolution rule of the sedimentary microfacies, the depositional model of the study area can be obtained.