An analysis of the source system and its effect on the reservoir of the middle-lower submember of 3rd Member of Shahejie Formation in Minfeng area, Dongying depression

Abstract: The Minfeng area is a vital part in oil and gas exploration of Dongying depression, and the analysis of source system has much significance in the study of sedimentary system and reservoir evaluation. Ancient landscape controlled the fundamental pattern of the distribution of the sedimentary system, whereas the downthrow side of Chennan fault, the interior of Minfeng sag and the Xinzhen area provided the accommodation space for the deposition of sand bodies. Characteristic elements and sandy disperse system suggest that, during the period of the generation of middle-lower 3rd Member of Shahejie Formation (Es31-2), there were three source systems around the Minfeng area, and the sedimentary primitive components came from Chenjiazhuang salient in the north, Qingtuozi salient in the east and the external basin water system through Guangrao salient, and the main fractures of F1 and F2 of Xinzhen structure might have served as the main source channels in southward direction. The southern part of the sedimentary system controlled by the eastern source system met the northern branch of the southern source system. The primitive sedimentary components constituted the foundation of the reservoir, which caused the differences in the reservoir space and physical properties. The reservoirs in the facies belt of the delta front in the east and the mixed resource area are characterized by weak compaction with well-developed primary intergranular pores and have favorable porosity and permeability with high oiliness, thus superior to the physical properties of reservoirs in the south and north，with the reservoirs in the mixed-resources area having the best oiliness.