Successful QI and Seismically Constrained Reservoir Modelling for a Clastic Onshore Oil Field in Oman

A quantitative interpretation (QI) study has successfully predicted the distribution of sands and shales in the Upper Gharif. This was indisputably confirmed by three wells drilled after completion of the QI study. By applying a range from basic to high "tech" QI techniques, a workflow has been developed that enables us to delineate channel sands with challenging rock properties at a relatively deep target onshore Oman. As a result, a confidence map is constructed that assigns areas with different probabilities to encounter these channel sands. Then, building on this success, the first 3D Close-the-Loop project in Petroleum Development of Oman (PDO) ever is initiated. This methodology strives to obtain an accurate as possible static reservoir model, which is consistent with all available subsurface data. The workflow basically consists of two steps, i.e. a modelling and an inversion part. The latter, in case of disagreement between modelled and measured data, updates the initial reservoir properties. Ultimately, the subsurface uncertainties are considerably reduced resulting into improved reserve estimates. The significance for PDO is that although this technology is well established in most major oil companies, this is the first time it has been successfully applied on a PDO seismic data volume.