Abstract

Previous quick-look probabilistic log analyses have led to inconsistent results between various datasets. This inconsistency caused uncertainty in the development scenario for a carbonate field with complex pore geometry. To address these concerns, all available petrophysical data have been integrated for new GIIP and reservoir simulation input. The integration is characterized by determining four calibration end points, two for each volumetric component: porosity and hydrocarbon saturation. An evaluation that calibrates end points provides the correct rates of change across the spectrum of these two variables and reports the correct hydrocarbon pore volume, from zero through to its highest values. It will also make more correct use of limited and possibly non-representative core data, a common problem during appraisal. The integration uses normalized log data, routine core data, 'Sw100 zones', variable cementation exponents and resistivity integrated core-log, capillary pressure Skelt functions. Skelt functions here replace mercury injection look-up tables to provide a precise up-scaling of the directly measured air-brine capillary pressure gas volumes, via their proper integration with the larger routine core and log data sets. This integration provides new found confidence allowing the development of a complex carbonate gas field, despite very limited new data acquisition and low overall cost.