Oil Layer Correlation And Sedimentary Facies Analysis Of The Oil Group ? Of The Lower Es3 In Gubei Sag

This thesis takes the I oil group of the lower third members of Shahejie Formation in the Gubei Sag as the research object,guided by the high-resolution sequence stratigraphic theory and basic principles of sedimentology of,through literature research,the use of drilling and logging data and Core observation methods are used for analysis,research and interpretation,high-precision sequence framework,sedimentary microfacies analysis,sand system distribution,and other studies have been carried out,and further well location recommendations have been put forward.Based on the interpretation of drilling and logging data,using high-resolution sequence straigraphy theories and technical methods,a complete mid-term base-level cycle was identified in the I oil group of the lower third member of Shahejie Formation in the Dongciwa.The top and bottom are large-scale lake flooding surfaces.It is further divided into 4 short-term cycles with the three sub-flooding surfaces inside it as a boundary,and each short-term cycle includes two semi-cycles of base-level down and base-level up.On this basis,it is further divided into 4 sand group.The sand groups are named I4,I3,I2,I1 from bottom to top.Through well-logging comparison,the highfrequency sequence stratigraphic framework of the first set of oil groups in the lower Es3 sub-member of Dongciwa was established,and the development characteristic of the strata were determined.Through core observation and drilling and logging data analysis,the study of sedimentary microfacies constrained by the sequence framework was carried out.Braided water channels and water channels were identified in the first set of oil groups in the lower part of the third sub member of the East Sub-sag in the Gubei Sag,Four types of sedimentary microfacies,inter-channel,sheet,and deep lake,have clarified the sedimentary characteristic and identification marks of different sedimentary microfacies in the study area.Through logging data analysis,the distribution characteristic of the sand systems of each sand group are established.According to the basic principles of sedimentary,through the thickness,shape and distribution of sand systems,confined with the analysis of single wells and continuous wells,the plane layout of sedimentary microfacies of 4 related sand unit was drawn to clarify the sand groups in the sequence framework.Sedimentary facies distribution and evolution characteristic in the sequence framework of the first set of oil groups in the lower third member.Vertically and from bottom to top,the deposition thickness of the turbidite channel gradually increases and then decreases.The accumulated thickness of the sheet sand is larger,which is manifested as multi-stage superposition;on the plane,the lateral migration characteristic of the channel is obvious,with multiple fans-shaped sheets.Covering and above the mudstone in central and northern part of the study area.The turbidite channel is further divided into lateral migration type,composite type and vertical superposition type,of which lateral migration type and composite type are the main ones.The complete “Bauma sequence” can be seen in some wells,combined with the formation and structural development background.Established the deep-water gravity flow deposition model of the target interval in the study area.Considering the sequence stratigraphic position,sedimentary facies distribution,oil layer distribution and reservoir profile and other factors,it is determined that three azimuth development evaluation wells are recommended to be deployed.