Zahra Riazi
Despite the popularity of permeability and porosity relationships in the rock typing approaches of the sandstones, their application is limited in the carbonates. It stems from secondary porosity, and heterogeneities in the carbonates, which leads to weak correlation between them. Mismatching of carbonate rock samples with their defined rock types by permeability and porosity relationships pronounces this shortage in the laboratory and thin section studies. This study has considered the product of irreducible water saturation and porosity, which is indicated by Bulk Volume Water (BVW) was examined as a possible standalone substituted rock typing method for carbonates in this study. Its outcomes were successfully validated by Mercury Injection Capillary Pressure (MICP) curves and compared with the Reservoir Quality Index (RQI) method in three carbonate fields.
Results of rock typing in the three different carbonate fields revealed a more satisfactory match between classified rock types using the BVW and their equivalent MICP curves in comparison with RQI method. Moreover, smaller number of rock types were defined in the three carbonate fields using the BVW method, which leads to improve further modellings. Therefore, this method can be a more appropriate method for carbonates having a poor permeability-porosity relationship.
Moreover, porosity and irreducible water saturation are easily attainable from petrophysics well logs in the most field wells, contrary to extensive lab works that permeability data needs to achieve. Its outcome is also straightforward to feed into the static and dynamic models. Although, handling a great deal of data may seem an issue for this method, which the prepared MATLAB code has tried to facilitate in this study.