Sedimentary Characteristics And Favorable Reservoir Distribution Of Es2 In Ying 17 Fault Block

Ying 17 fault block is located in the north flank of Dongying dome anticlinal belt in the central uplift zone of Dongying Sag,Jiyang Depression,and is currently in the stage of secondary oil recovery.In this paper,the sedimentary characteristics and reservoir characteristics of the Es2 in the study area are studied by core observation,casting thin section identification,scanning electron microscopy,X-ray diffraction and other analytical and laboratory methods,making full use of core data and logging data.Through fine stratigraphic division and comparative study of the Es2 in Ying 17 fault block,the strata in the study area are high in the East and low in the west.The lower part of Es2 has a large fluctuation,while the upper part has a relatively small fluctuation.According to the sedimentary facies markers and logging facies,the sedimentary facies and microfacies types are identified,the distribution law of sand body and the distribution characteristics of sedimentary microfacies are determined,and two sedimentary subfacies are developed in the study area.The lower part of Es2 is braided river delta front subfacies,which mainly develops estuary bar,underwater distributary channel,underwater distributary channel and sedimentary microfacies.Far bar,front sheet sand,interdistributary bay and pre-delta mud microfacies;upper member of Es2 is braided river delta plain subfacies,which mainly develops braided channel,heart beach,channel margin and flood plain microfacies.The main rock types in the study area are feldspar sandstone;the reservoir space is mainly primary intergranular pore,followed by secondary dissolution pore;the pore throat type is mainly macroporous coarse throat and mesoporous medium throat;the diagenesis is mainly compaction,pressure dissolution and cementation;the reservoir evaluation is carried out according to the reservoir classification criteria of CNPC.Class II reservoirs with high porosity and permeability and Class III reservoirs with medium porosity and permeability are mainly developed in the study area.Based on the above research results,it is determined that the favorable reservoir range is estuary bar,underwater distributary channel,distal bar,and center beach and braided channel microfacies of upper sub-member of Es2.The porosity is generally greater than 18%,and the permeability is generally greater than 100×10^-3?m².