Sedimentary Facies of Member 3 of Liushagang Formation of WZ10-3 Oilfield and Surrounding Areas in Weixinan Sag

Key words: 
• Weixinan sag /
• WZ10-3 Oilfield /
• member 3 of Liushagang Formation /
• high-resolution sequence stratigraphy /
• sedimentary facies /
• fan delta

Abstract: In order to promote progressive exploration and development in WZ10-3 Oilfield and surrounding area, the fine sedimentary facies study in oil region was carried out. Guided by the high resolution sequence stratigraphy theory, in combination with core, logging, log and seismic data, on the basis of recognition of different levels sequence interfaces and the types of maximum lake flooding surface, the Member 3 of Liushagang Formation can be divided into two long-term base level cyclical sequence and eight middle-term base level cyclical sequence. By analyses of individual well sedimentary facies, section sedimentary facies and plane sedimentary facies, 3 sedimentary facies of alluvial fan, fan delta and lacustine were identified in the Member 3 of Liushagang Formation, and microfacies were divided, facies belt ownership of debris flow deposit was discussed systematically. Debris flow deposits developing in channels were divided into 3 types, i.e., channels, distribution channels and subaqueous distribution channels microfacies. While individual developmental debris flow deposits were divided into 2 types, i.e., subaerial non-channelized and subaqueous non-channelized debris flows microfacies. On the basis of these, sedimentary facies distribution and sedimentary evolution rule of MSC1 to MSC8 of the Member 3 of Liushagang Formation were discussed, and sedimentary models were established finally.