Subdivision And Reservoir Evaluation Of Gravel Rock Mass In The Fourth Member Of Shahejie Formation In Zheng Nan Slope Belt Of Dongying Sag

The glutenite fan in the fourth member of the Shahejie Formation of the Zheng Nan Slope in the west part of the north zone of the Dongying Depression is extremely developed.Due to the distribution of the glutenite fan and the complexity of the reservoir,the prediction of effective reservoirs is difficult and the overall degree of confirmation is low.The paper is guided by the glutenite fan deposition model,makes full use of geophysical data,combines seismicity with geology,and carries out the zoning and reservoir evaluation of gravel rock mass.The paper obtained the following research knowledge:(1)Through the study of boundary fault activity in the southern slope belt of Zheng Nan,it is proposed that the strength of the boundary fault activity and the length of the activity time control the stage and scale of the glutenite fan in the study area,and establish the quadratic accumulation-return overlap Deposition mode;(2)Through the seismic target processing to improve the accuracy of intrusive imaging of sandstone and conglomerate,combined with the method of sequence stratigraphy and the high-resolution sequence cycle of logging,etc.,the phases of the glutenite fan are finely divided and the Divided into 13 phases,the sub-effective identification,classification and description techniques for the gravel rock mass deposition period suitable for the study area were formed;(3)Using geostatistical method to determine the lower limit of reservoir porosity in the study area is 5% and the lower limit of permeability is 0.8md.The effective reservoir evaluation criteria for gravel rock mass in the study area are established;(4)Using a variety of geophysical methods to carry out comprehensive prediction of effective reservoirs,forming a three-step forecasting method,depicting the spatial distribution pattern of effective conglomerate reservoirs at different scales and different angles,and realizing 13 favorable facies zones.Forecasting,prediction of porosity,detection of oil-bearing properties,implementation of the gravel rock mass reserves,and favorable exploration targets.