Prediction of reservoir properties using inverse rock physics modelling in Kanywataba Exploration area Albertine Graben

Abstract

In this study, we use the concept of inverse rock physics modelling to analyse reservoir properties of the Kanywataba Exploration area and with focus on their lateral distribution away from the Kanywataba well. The procedure employs rock physics models calibrated for the basin constrained by seismic inversion data where also non-uniqueness and data error propagation issues are taken into account. Both seismic and well log datasets are used in the data calibration. The procedures enable us to obtain the most likely estimate mean, weighted mean and posterior mean of the reservoir properties. We obtain a good match between measured and modelled porosity values. Misfit between observed and predicted lithology is mainly attributed to the uncertainties in defining the correct mineral properties. The integrated approach reveals that high porosities correlates with low clay volumes, furthermore, indicating two distinct reservoir units in the basin interpreted as Oluka and Kakara Formations. Fluid saturation data were less successfully predicted, but was most probably a result of lack of real saturation logs for use in the calibration of rock physics model, instead, predicted saturation logs based on Archie's law were used in the calibration process. This analysis is first of its kind in this basin and therefore exhibits high level of novelty in reservoir property determination of this area.