Characteristics Of Lake Carbonate Reservoir And Comprehensive Logging Interpretation Evaluation

With the deepening of exploration and research in the Yingxi area,it has shown that the upper member of the Lower Ganchaigou Formation(E₃²)of the Oligocene is very rich.However,the area is located in the Yingxiongling basin-like structural erosion zone in the stratigraphic depression of the western Qaidam Basin.The northwestern section has been affected by plate tectonics and geological sedimentation for a long time,resulting in complex lithology of this type of reservoir,many types of minerals and reservoir types,diversity of pore structures,and strong reservoir heterogeneity.Therefore,it is difficult to obtain reservoir parameters and the effective reservoir division is not clear.Therefore,it is of great significance for the analysis of reservoir characteristics and comprehensive interpretation and evaluation of reservoirs in Yingxi area.Based on the interpretation of comprehensive logging data,this study is aimed at difficulties in obtaining reservoir parameters and unclear division of effective reservoirs.this study used lithology scanning logging,diffraction whole-rock analysis,lithological column sampling and other analysis methods to analyze the reservoir characteristics(lithology,physical properties,Oil-bearing and electrical properties)to conduct research and analyze the relationship between reservoir characteristics in Yingxi area,and then use lithology scanning logging to identify the reservoirs in Yingxi area,and to classify the reservoir types,using lithology scanning logging,electrical Imaging logging,element logging,and nuclear magnetic logging are used to evaluate reservoirs in Yingxi area,establish effective porosity,porosity spectrum,fracture calculation and saturation calculation methods,and improve the accuracy of reservoir parameter calculation.Finally,Combining the influencing factors of the reservoir,using the comprehensive analysis of porosity and fracture parameters,the classification chart of the reservoir is constructed,and the comprehensive classification standard of effective reservoir is established to effectively classify and divide the reservoir.Studies have shown that the lacustrine carbonate reservoirs in the study area have low porosity and ultra-low permeability.The main lithology of the reservoirs is marl-bearing dolomite and argillaceous lime dolomite.Using electrical imaging logging,reservoirs can be divided into four types:strong layered,weakly layered,dark patchy and massive structure.Reservoir evaluation standards and classification charts are constructed by parameters such as matrix porosity and fracture porosity to evaluate the reservoirs.The results show that the classification standards and classification charts are effective in the evaluation of reservoirs and are useful for improving lacustrine carbonate reservoirs.Log interpretation has important guiding significance and application value.