Research On Logging Interpretation Methods Of Low Porosity And Permeability Reservoirs In Su-bei Basin

After decades of exploration in Jiangsu oilfield, there have found a series of low porosityand permeability oil-bearing blocks. At present, there have been not relevant logginginterpretation methods for lacking of enough recognition to the formation mechanism and thelaws of accumulation. It makes the interpretation more and more difficult, which affect thein-depth development of exploration. Therefore, research on logging interpretation methodsof low porosity and permeability reservoirs in Subei basin is very important.In this paper, we take the low porosity and permeability reservoir of Gaoyou and Jinhudepression in Subei basin as the research target, combining the predecessors’deep research tothe formation mechanism and sedimentary microfacies, at the same time combining thegeology and logging, we take logging comprehensive evaluation research based on thedifferent types and blocks. We mainly take researches on the essential characteristics ofreservoir,including sedimentary,rock and mineral,pore and throat,furthermore analyse thecorrelation between sedimentary microfacies and physical properties; after looking for themain critical elements,we take categories by combining the predecessors’deep research of thecauses, establishing the interpretation models of effective porosity, permeability, saturation;wetake research on the lower limit of the effective reservoir and take futher reservoir categoriesby using the comprehensive evaluation index combining with the logging reservoirparameters and testing data, realizing the effective combination of geology and logging.Futhermore we take the fluid identification and select methods to the low porosity andpermeability reservoir.According to different reservoir types, we optimize fluid identificationmethod that is suitable for the reservoir types and has a good application effect. In the end, itformed a set of comprehensive technical means to identify fluid properties.The corresponding interpretation methods proposed in this paper aiming at the lowporosity and permeability reservoir in Subei basin make the relative error between the reservoir’s quantitative results and core analysis results reach the industry standard, thecoincidence rate achieved more than83%, obtaining a good application effect.