Sedimentary Microfacies And Sand Body Distribution Regularities Of The Southeast Chang 6 In Wanggoumen Oilfield

This paper studies the distribution of sedimentary microfacies and sand bodies in the southeast area of Wanggoumen Oil Region.The main horizons studied in this paper are the Triassic Yanchang Formation Chang 6 reservoirs.Through the control of regional markers,combined with the principles of sedimentary cycles and formation thickness,the composition of Chang 6 reservoirs is chang 611,chang 612,chang 621,and chang 622.,chang 631,chang632.Based on the lithological and electrical characteristics,the petroelectric characteristics of each small layer are described in detail,and through the multi-well section comparison study,the fine stratigraphic division and contrast grid of the Chang 6 oil layer group in the study area are established to provide sedimentation for the study area The study of microfacies and sand body distribution law laid the foundation.Based on the identification and identification of the main sedimentary facies of the sedimentary lithofacies and geophysical logging facies,combined with the analysis and research of various test data,it is considered that the Chang 6reservoir in the study area belongs to the delta front subfacies.Microfacies such as underwater diversion channels,natural dikes,diversion bays,estuaries and mat sands are developed in the study area.Among them,the microfacies sand body of the underwater diversion channel is the skeleton sand body of the Chang 6 reservoir.The middle and underwater diverted river channels of Chang 611 and Chang 612 are relatively developed,and the sand bodies are well connected.The development of the sand body of the underwater shunt channel on the plane is controlled by the plane distribution of the sedimentary microfacies,which are mainly distributed in a north-east-south-west direction.During the Chang 6 period,the sand bodies in the study area mainly developed branched channels with northeast-southwest,northwest-southeast and flowery estuary sand dams.Among them,the overall sandstone content of small layer chang 612 and small chang 611 is larger.