An evaluation technique to help define net pay and refine reserve esti- mates, and to aid in optimizing productivity, was developed for the Cardium sand in the Pembina Field, Alberta, Canada. This technique is based on rock type as determined from mercury injection data. An empiri- cal correlation between effective pore throat or aperture radius and the ratio of permeability to porosity (k/0) was applied to all core analyses on the Pembina "G" lease to generate suites of reservoir parameters such as net pay, pore volume, and flow capacity. When correlated with lease well productivity, they revealed wells with potential for improved produc- tivity. Additional data from other leases in the field support the k/O correlation validating its application to Cardium sand areas in the Pembina field. The technique is ideally suited to computer application.