The Study On Reservoir Geological Model Of 10^th Sand Group In Second Member Of Shahejie Formation In The Shishen 100 Fault Block,Shinan Area

Shengli Oilfield has entered the late stage of high water-cut development.In the early stage,the thin sand body with a low degree of production as a non-major layer has become an important target area for tapping the potential of remaining oil.In order to better implement the deployment of mud-packed sand-type thin sand body well patterns and the implementation of development measures,the target area is the 10^th sand groups of the second member of Shahejie Formation(ES₂¹⁰)in Shishen 100 fault block.Combining the results of predecessors,with the help of contrast markers,a small-layer fine stratigraphic framework is established.And through the analysis of multiple facies markers,clarify the distribution characteristics of the sedimentary microfacies in the area.And use this as a constraint to dissect the characteristics of reservoir porosity,permeability and oil saturation.Finally,a three-dimensional reservoir model for oilfield development is established through the principle of facies control modeling.The following points of understanding have been achieved.（1）The pre-delta argillaceous rock at the top of ES₂¹⁰ has obvious lithoelectric characteristics and relatively stable distribution.Under its control,ES₂¹⁰ is divided into 10small layers,the upper 1-5 layers are dominated by positive cycles,and the lower 6-10 layers are dominated by reverse cycles.Both upper and lower are characterized by mud-packed sand.（2）ES₂¹⁰of Shishen 100 fault block is a monoclinic structure as a whole.The microstructure types in the area mainly include small flexures,micro terraces,and small broken noses.The tail end of the Shinan fault controls the structural style of the entire fault zone.Each microstructure feature has good inheritance in ES₂¹⁰.（3）The upper part of ES₂¹⁰ mainly develops the deposition between the thin underwater distributary channel and the underwater distributary channel of the braided river delta front,with a small thickness.In the upper 4-5 small layers,the middle and underwater distributary channel sand bodies are contiguously distributed,and the overall scale is large.The lower 6-8small layers of underwater distributary channel sand bodies and estuary dams are contiguously distributed on the plane,and the overall scale is large.The other small layers of sand bodies are relatively small in scale.（4）The reservoir properties of ES₂¹⁰ belong to low porosity-low permeability reservoirs,and the overall physical properties of the lower 6-10 small layers are better than the overlying1-5 small layers.The channel is relatively narrow when the upper sand group is deposited.The hydrodynamic force is relatively weak,the shale content is dispersed,the original porosity and permeability are low,and the loss of porosity and permeability is also greater after the later diagenesis.Only at the fork and estuary dam of the distributary river where the water flow is relatively stable,the sediments are sorted better and the porosity and permeability are higher.（5）In the three-dimensional model of the reservoir,the fracture of the 10 sand layer group has obvious regularity.The physical parameters of the reservoir change rapidly in three-dimensional space,and the sand bodies of high-quality reservoirs are distributed like sweet spots.Corresponding to the main body of the underwater distributary channel and the estuary bar and other microfacies belts,the crude oil in the main pay zone is mainly concentrated in the corners of the fault.The established reservoir model can well reflect the characteristics of the reservoir in the zone,providing a strong basis for the later deployment of well positions and adjustment of development measures...