新疆克拉玛依油田八区上二叠统下乌尔禾组河控型扇三角洲沉积

Fluvial-dominated fan delta sedimentation of the Lower Urho Formation of Upper Permian in the 8th Area of Karamay Oilfield, Xinjiang Autonomous Region

从岩心、薄片等实际资料着手，结合EMI成像测井等现代技术研究，认为新疆克拉玛依油田八区上二叠统下乌尔禾组属河控型扇三角洲相沉积，并识别出2种亚相和9种微相：2种亚相是扇三角洲平原和扇三角洲前缘亚相。9种微相是辫状河道沉积、漫流沉积、泥石流沉积、筛滤沉积、水下分流河道沉积、水下分流河道间沉积、水下天然堤沉积、碎屑流沉积及颗粒流沉积。同时，以成像测井资料为主要依据，结合岩石粒度及成分特征分析，表明研究区下乌尔禾组5个时期的物源方向不尽一致，表现为从早到晚，由第5亚期至第1亚期，物源方向由以西南方向为主，逐渐变为以西北为主。与物源变化相对应，沉积相也呈现有规律的变化。本文在对沉积相进行详尽研究的基础上，深入解剖了克拉玛依油田上二叠统下乌尔禾组的沉积微相特征，阐明了沉积相的展布和演化规律。

Based on core data, slice, and so on, combining with many modem technologies, such as the EMI image logging technique, etc. , it is concluded that the Lower Urho Formation of Upper Permian is the fluvial-dominated fan delta facies in the 8th Area of the Karamay Oilfield, Xinjiang Autonomous Region. Two subfacies, i.e., the fan delta plain and fan delta front subfacies, with poor development of the pro-fan delta, and nine microfacies are identified. The fan delta plain subfacies includes braided channel, unconcentrated flow, mud flow and sieve deposit microfacies. The fan delta front subfacies includes subaqueous distributary channnel, subaqueous interdistributary channel, debris flow, subaqueous natural barrier and grain flow microfacies. Meanwhile, we propose that the material supplying directions were not coincident in the 5 stages of the Lower Urho Formation based on analysis on image loggingdata and features of granularity and petrologic composition of the Urho Formation. The material supplying direction varied from southwest to northwest from the early period to the late period （the fifth subage to the first subage）. Corresponding to the material supplying direction, the sedimentary facies changed regularlly. Based on the detailed studies of sedimentary facies, the microfacies features of the Lower Urho Formation of the Upper Permian are analyzed profoundly and the distribution and evolution of sedimentary facies are also described in the Karamay Oilfield.