Research Of Distribution Of Sand Body And Sedimentary System Of The Second Member Of Kongdian Formation In Cangdong Sag, Huanghua Depression

Cangdong Sag is located in the south of Huanghua Depression, between Yangsanmu and Dengmingsi. The area of the exploration is4700km2. North of the sag is Kongdian Salient, south is Wuqiao Sag, west is Cangxian Salient, east is Xuhei Salient. The main tectonic units is consist of Cangdong and Nanpi Secondary Sag, Kongdian Salient, Wumaying Salient, Xuhei Salient, Cangshi Nosing Tectonic Belt and Xiaoji Tectonic Belt. Cangdong Sag is the area that the oil and gas resources exploration degree is not high in the Bohaiwan Basin. But in recent years, it become hot spots of exploration, especially, the Second Member of Kongdian Formation(Ek2) is the key layer about oil and gas resources, and Cangdong Sag become the second oil-rich sag in Dagang Oil Field.Because the well data and seismic data is lack in this area, the location of provenance and the sedimentary facies division, especially microfacies, is not clear. It restricts the exploration deployment and development in this area. For solving these problems, in this thesis, Cangdong Sag of Huanghua Depression in Bohaiwan Basin is taken as the study area, and Ek2is taken as the purpose layer. According to the latest data of regional structure, logging, seism, deposition and so on, this thesis Combines previous research results, By using the basic principles and methods of sedimentology and the research way of horizon, area, provenance, facies, system, Reveals the distribution regularity of sedimentary system and sand body space, it provides a scientific basis for stratigraphic lithologic reservoir exploration of Ek2in Cangdong Sag, Huanghua Depression.This thesis consulted Gravity anomaly and seism data of the area and comprehensive used the method of heavy mineral and clastic rock analysis. On the basis of the available data of old well, it comprehensive researched the latest data of seismic, logging and Mineral rock. Research shows that the provenance exist in the southeast, southwest, northwest, northeast of the lake basin. Further more, it can be identified ten sub-provenance that like Wu maying, Yesanbo, Shenvsi and so on. it forms the characteristics of multi-provenance distribution in the lake basin.Using the data of the core, logging, seism and so on and according to rock types, sedimentary structure and profile structure, this area can be identified four sedimentary facies types that include the Braided River Delta, Beach Bar, Turbidite Fan and Lake. It is clear that the characteristics of the distribution of the sedimentary system in different provenance. In the plane, the area can be divided into four sedimentary system types, Wumaying sedimentary system in the south, Shenvsi sedimentary system in the west, Kongdian sedimentary system in the north and Wanghaisi sedimentary system in the east.In the base of research about sedimentary facies and the analysis of physical property in different sedimentary microfacies types, the high quality reservoir is the sand body in underwater distributary channel and estuary dam of braided delta front of Ek2in Cangdong Sag.