Sedimentary Facies Study And The Layer Comparison Of Kendong6 Fault-block, Zhanhua Depression

Kendong6 fault-block of Gu’nan sag, is located at the hanging wall of Kendong Fault, the southeast of Zhuahua depression, and forms a fault nose structure. Historically, the study area is in its late development period and it is difficult to discover structural reservoirs of large scale. What’s more, a lot of problems appears, such as complex oil-water relationship, unclear sandstone distribution and connectivity, strong heterogeneity. Given these problems, it is necessary to study sedimentary facies of the area in order to discover subtle reservoirs and exploit residual oil.High-resolution sequence stratigraphic framework is established. The 2nd and 3rd member of Shahejie formation is divided into 4 half-circles of 3rd-order sequence, and then 7 half-circles of 4th-order sequence, which are named A, B, C, D, E, F and G bottom-up. Unconformity surface, flooding surface and marker bed of special lithology considered as boundaries,43 thin layers are recognized and correlated in the 4th-order sequence framework.By analyzing cores and well-logging curves, turbidite fan, braided delta and lacustrine facies are recognized. Specifically, turbidite fan and lacustrine facies are identified in A half-circle, underwater distributary channel, mouth bar and underwater distributary bay in B, C and D, and distributary channel, splay and interdistributary bay in E, F and G.The aim layers have a mean porosity of 15%～25% and an average permeability of 50-600mD. Both the porosity and the permeability of the 4 main thin layers are obviously controlled by sedimentary facies. The main thin layer A1 has a predominantly good physical property for turbidite sandstone, C1 and C6 underwater distributary channel and mouth bar, and G5 distributary channel.