Evaluation Techniques of Bedrock Reservoir Effectiveness in the Northern Songliao Basin
To address the problem such as the complex bedrock lithology,dense reservoirs,fracture development,low calculation accuracy of reservoir parameter and difficult evaluation of reservoir effectiveness in the northern Songliao Basin,a new three-dimensional lithology identification method of"original rock+composition+structure"was proposed;the effective porosity model for variable skeletal density based on M and N was established by calcu-lating the slope M using the acoustic-density rendezvous plot and the slope N using the neutron-density rendezvous plot;the gas saturation model of fracture-containing reservoir was established by studying the conductivity mecha-nism of bedrock and correcting the additional conductivity of fractures;the effective thickness standard of bedrock reservoir and the classification standard of effective reservoir were determined by considering the effective porosity,secondary porosity and the degree of fracture development.The application results show that the lithologic interpre-tation compliance rate of this set of technology can reach 87.5%,the gas-bearing formation identification compli-ance rate reaches 88.5%,and the calculation accuracy of porosity and saturation meets the requirements of the res-ervoir specification.The study results can provide technical guarantee for the geological exploration and reserve e-valuation of bedrock reservoirs in the northern Songliao Basin.