Study On Reservoir Architecture And Remaining Oil Distribution Of Shallow Water Delta In The Fourth Member Of Quantou Formation Of Xinmin Oilfield

In this paper,guided by Logging Geology and Reservoir Geology,based on stratigraphic division and correlation and study on sedimentary microfacies,the framework single sand bodies and its internal architecture of shallow water delta of the fourth member of Quantou Formation of Min 1 Block in Xinmin Oilfield are depicted in detail by using core,logging and production data.Then the 3D geological models are built up and the reservoir numerical simulation is done.The distribution of remaining oil is studied and the control of reservoir architecture on remaining oil distribution is also analyzed with the results of numerical simulation.The isochronal stratigraphic framework of the fourth member of Quantou Formation in study area has been established.The fourth member of Quantou Formation is divided into four sand groups and twelve layers,and the fourth,seventh,tenth,eleventh and twelfth layers are further divided into two single layers.The development characteristics of sedimentary facies of the fourth member of Quantou Formation in study area have been clarified.With the supply of BaokangTongyu river system,shallow water delta is developed in the fourth member of Quantou Formation,and plain subfacies and front subfacies are identified.The deltaic plain includes five microfacies which are distributary channel,natural levee,crevasse splay,floodplain sand and inter-distributary channel.The deltaic front includes underwater distributary channels,underwater inter-distributary channels and sheet sand.The development characteristics of framework single sand bodies and its internal configuration of the fourth member of Quantou Formation in study area have been clarified and the architecture model has been established.In delta plain,meandering distributary channels which have ability of lateral erosion are developed.The spatial contact styles of channel sand bodies are mainly tangency and superposition.There are lateral accretions arranging in diagonal form inside channels.In delta front,straight underwater distributary channels which have weak ability of downcutting and bifurcate massively are developed.The spatial contact styles of channel sand bodies are mainly splicing and separation.Inside underwater distributary channels there are vertical accretions which distribute in horizontally across channels and deposit forward along channels.The research on geological modeling and numerical simulation has been done.Structural model,facies model,sand skeleton model and attribute model are established in turn,and the above geological models are used for numerical simulation after coarsening.Then the historic change and present quantitative distribution of remaining oil of single sand bodies can be obtained by historic matching.With the results of numerical simulation the control of framework single sand bodies and its interlayers on the distribution of remaining oil has been illuminated and the distribution models of remaining oil have been established.There are three types of remaining oil including remaining oil controlled by single sand body contact styles such as tangency and superposition,remaining oil controlled by abandoned channels and remaining oil controlled by lateral accretions.There are also three types of remaining oil including remaining oil controlled by single sand body contact styles such as splicing and separation,remaining oil controlled by vertical accretions and remaining oil controlled by well pattern.