System and method for porosity estimation in low-porosity subsurface reservoirs

A method is described for porosity mapping of low porosity subsurface reservoirs using seismic data and well logs. The method may compute dry-frame rock properties using fluid substitution modeling based on the well log data; perform porosity expansion of the dry-frame rock properties based on rock physics to generate expanded rock properties; generate synthetic seismic data based on the expanded rock properties; calibrate the seismic dataset with the synthetic seismic data; generate an estimated porosity map based on the calibrated seismic dataset and the synthetic seismic data; and identify geologic features based on the estimated porosity map. The method may be executed by a computer system.