Study On Fluid Properties Identification Technology For Tight Sandstone Reservoir

During the exploration and development process of the Xiaochengzi Gas Field,we founded that the main strata has a complicated gas-water relationship,the nature of the fluid was difficult to identify,and the development potential was also unclear.Therefore,it is urgent to guide the formulation of exploration and development plans for the Xiaochengzi Gas Field through the secondary logging interpretation and fluid property identification,to facilitate the rapid and efficient development of the research area.Combined with the core analysis,testing,logging and development data of the Xiaochengzi Gas Field,described the geological characteristics of gas reservoirs briefly and carried out the analysis of the relationship between the four characteristics of the reservoir.Through systematically analyzing the logging response characteristics of more than 30exploratory wells and appraisal wells in the main gas-bearing formations of the Quantou and the Denglouku in the study area,sensitivity logging curves that can effectively identify the fluid properties of the gas reservoir were picked out.The conventional logging identification methods(three porosity difference-ratio,curve overlap,cross-plating,apparent elastic modulus coefficient,array induction)and the new logging technology identification methods(dipole shear wave,nuclear magnetic T₂spectrum)were used to identify thegas-water Layers.Due to the lack of the application of new logging technology in most wells,the 3D layout method and gas reservoir identification factor method based on multi-source information fusion have been established to determine the fluid properties.Follow the idea of core calibration logging,a fine logging interpretation model of reservoir parameters was constructed,and the lower limit of effective thickness was determined by the cumulative frequency method,the minimum flowing pore throat radius method,and the saturation chart.Through the programming of the logging interpretation model,we have realized the computer to automatically process and comprehensively interpret the logging data.Relying on the results of logging secondary interpretation and fluid property identification,combined with production performance,well history analysis,and gas reservoir dynamic and static characteristics,the development potential layers were screened out.The main understandings of this dissertation are as follows.Three-porosity logging,especially compensated acoustic and compensated neutron logging,are sensitive to gas and water formations.Array induction logging also has good response characteristics to gas and water formations.The conventional logging identification methods represented by the apparent impedance-compensated neutron intersection method can better identify the fluid properties in the study area,but the identification accuracy for poor gas and tight layers is lower than that of new logging technologies.The recognition accuracy of the three-dimensional chart method and gas reservoir recognition factor method based on multi-source information fusion is higher than that of the conventional logging method,and the recognition results are more consistent with the production performance.Logging secondary interpretations have screened out 30 potential layers,which are distributed in CS2,CS6 and CS615 three well areas.