oa Reservoir heterogeneity and development strategy of the Mauddud Reservoir undergoing pattern water flooding in Raudhatain field, northern Kuwait

The Albian Mauddud Formation contains a giant carbonate reservoir in the Raudhatain field. It has a production history of 45 years, divided into two phases: production from depletion drive for the first 40 years followed by inverted 9-spot pattern injection. During the first phase the reservoir pressure dropped close to the bubble point with less than 3.0% recovery. The reservoir has no aquifer support and the reservoir properties deteriorate towards the flank and to the bottom. The analysis of static and dynamic data has brought-out the inherent heterogeneity of the reservoir. On a macro-scale, faults act both as baffles and conduits to fluid flow. Reservoir layers show distinct variation in flow properties, both areally and vertically. The uppermost producing layer is more productive towards the flank of the field. The integration of production logs (PLT), core and log data indicated the layer to have more fractures with lighter oil in such areas. Higher production in crestal areas from other layers is due to the development of secondary<br>porosity and the preservation of primary porosity due to early oil migration. With pattern sea-water flooding, carbon-oxygen (C/O) logging is being used to monitor the water movement. Thief zones have been identified from PLT and core data and substantial water sweep occurs in these zones even though these are not perforated in most of the producers. Water encroachment is being closely monitored and remedial action is being taken to improve the sweep efficiency. The flank areas of the reservoir with inferior flow properties and heavier oil are being strategically developed. Seismic attribute analysis, zonal testing and fluid characterization from advanced logging techniques are being used to delineate these areas. This presentation will discuss a multi-pronged<br>strategy of mapping reservoir heterogeneity and its use in optimal field development.