| Xinbei area is located in the south of Songliao Basin,the west slope of the northern Fuxin Uplift,and the territory of Balang Township,Songyuan,Jilin Province.After decades of exploration and development,the research focus at this stage is on lithologic oil and gas reservoirs with stronger concealment.Therefore,it is urgent to study the sedimentary characteristics,sedimentary microfacies,sedimentary evolution and sedimentary model of Fuyu oil layer in Xinbei area,providing a solid theoretical support for the prediction of the subsequent facies-controlled "dessert" in this area.Guided by the theories of sedimentology,reservoir geology and high-resolution sequence stratigraphy,this thesis comprehensively uses the detailed geological information data such as core,logging,and logging to divide Fuyu oil layer into 1 ascending half-cycle of long-term base-level cycle,4 medium-term base-level cycles(MSC1-MSC4)and 13 long-term base-level cycles(SSC1-SC13),and establishes the sequence stratigraphic framework of Fuyu oil layer in Xinbei area.Based on the previous research results,it is clear that the sedimentary period of Fuyu oil layer in Xinbei area is mainly controlled by the southwest Baokang provenance,and the channel sand body extends along the provenance in a southwest-northeast direction.The overall development of fluvial-controlled shallow delta deposits is further divided into two subfacies(fluvial-controlled shallow delta plain and front subfacies)10microfacies(distributary channel,abandoned channel,overbank sand,natural embankment,distributary bay,underwater distributary channel,sheet sand,sheet inner edge,sheet outer edge and underwater distributary inter-facies),there are mainly 4 stacking styles of channel sand bodies developed vertically,with vertical shear stacking,dislocation shear stacking,lateral shear stacking,and isolated distribution from bottom to top.On this basis,carry out the fine characterization of sedimentary sand bodies in the development area based on well data,predict the distribution characteristics of sand bodies in the evaluation area based on the remote sand body combination model,and finally implement the research on the plane distribution law of sedimentary microfacies in each short-term base-level cycle in the whole area.Under the overall condition of water advance,Fuyu oil layer has gone through four stages of development and evolution:(1)the initial stage of slight decline and then slowly rising stage;(2)The stage of rapid rise and continuous decline in the middle and early stage;(3)The rapid rising stage in the middle and late stage;(4)In the later stage,the rapid rise followed by a slight decline stage,and the high-energy river-controlled shallow-water delta plain,the medium-energy river-controlled shallow-water delta plain,the medium-low energy river-controlled shallow-water delta plain and the low-energy delta plain nearshore-front sedimentary area were successively developed.According to the above evolution rules,the sedimentary model of Fuyu oil layer in Xinbei area was established. |
