Lithofacies and electrofacies models for Mishrif Formation in West Qurna oilfield, Southern Iraq by deterministic and stochastic methods (comparison and analyzing)

Abstract

In this study, the researchers attempted to build models that are more accurate by using lithofacies data along the field. Using a wider field area and extended data from both electrofacies and lithofacies could provide an accurate model of the reservoir description that will be useful for future field developments. The stochastic and deterministic models were presented to build the facies model as the basis for the construction, comparison, and selection of the more accurate model of the Mishrif Formation in the West Qurna oilfield/Iraq. The results obtained from this study indicated that the Sequential Gaussian indicator simulation algorithm offered a more accurate stochastic model between lithofacies data extracted from 20 wells and electrofacies from 75 wells, while the Truncated Gaussian simulation algorithm has a better match than others for the distribution percentage of lithofacies and electrofacies. The stochastic model shows that Mishrif Formation consists of approximately 35–40% as carbonates, 32–35% as shale, and 28–30% as coarse sand, Dolomite, and other materials according to the SISIM and GTSIM, while the deterministic by the kriging algorithm referred to as 62%, 24%, and 14%, respectively. The best variogram that gives the best results indicated that the direction of facies distribution is mainly South-North with an inclination to North-West.