Rock Type-based Characterization and Petrophysical Analysis of the Silurian Acacus Sandstones, Ghadames Basin, Tunisia

Careful petrographic examination of sidewall cores from Acacus sands, combined with routine core analysis, XRD and SEM data allowed for identification of 5 discrete rock families. Integration of the petrographic and wireline data, particularly NMR (CMR) data, enabled the identification of the 3 principle reservoir rocks 80+% of the time. Starting at the pore scale and discriminating discrete petrophysical Rock Types with unique petrophysical properties yields a much more robust characterization of the reservoir than can be obtained by conventional evaluation techniques. The integrated approach should reduce logging costs by enhancing the ability to identify rock types capable of storing and producing fluids and through the generation of more accurate fluid saturation profiles. Distinction of Rock Types permits more coherent interpretation of porosity-permeability, capillary pressure and electrical properties data measured in the lab. Applying these data in log analysis allows for better saturation and net pay calculations. Finally, the integration of rock types with depositional environments ultimately leads to better and more meaningful reservoir mapping which can be used to better locate future wells.