Multi-scale elastic rock physics template for deep carbonate reservoir parameter prediction: a case study of the...

With the depletion of conventional oil and gas resources, global attention has shifted to deep unconventional reserves. Carbonate reservoirs account for a substantial portion of worldwide hydrocarbon reserves. However, their heterogeneous pore systems comprising pores, cracks, and vugs pose significant challenges for parameter prediction. Deep carbonate reservoirs exhibit complex pore structures, pronounced heterogeneity, and ambiguous seismic responses. To address these, we integrate the microscopic Gurevich squirt flow model with the mesoscopic Biot-Rayleigh theory, yielding a multi-scale elastic rock physics framework. This framework quantifies interrelations among microcracks, porosity, and P-wave dispersion. It also incorporates effects of fluid viscosity, temperature, and pressure on seismic wave attributes. Using the Voigt-Reuss-Hill average, differential effective medium theory, and Batzle-Wang equations, we construct a multi-scale elastic rock physics template for the Shunbei area, centered on P-to-S-wave velocity ratio and P-wave impedance. By combining this framework with seismic data, the template enables prediction of reservoir porosity and crack porosity. Results demonstrate that the template-based method effectively delineates high-quality reservoirs. Predictions align well with well-test data from three wells, validating the approach.