Field Development Plan Optimization of Mishrif Reservoir in Majnoon Oilfield

The paper discusses the optimized field development plan for Majnoon with special emphasis on the major Mishrif reservoir. Mishrif is the largest reservoir in Majnoon with expected OIIP of more than 20 billion bbls and a large areal coverage. One of the key uncertainties in Mishrif is the reservoir performance under sustained water injection. The base case development plan for Mishrif is initial depletion followed by inverted 5 spot 100 acres pattern injection. Since reservoir is quite heterogeneous single development scheme throughout the field is not suitable. Several iterations for development plan optimizations including voidage replacement optimization resulting in a ‘hybrid phased’ development is planned with ‘5 spot 100 acres pattern injection’ in the crest and ‘200 acres depletion’ for the flank. The development plan optimization was done by integrating the results from the reservoir simulator into an in-house developed Excel based tool. The Excel based tool was used to analyze the large simulation dataset. This effort led to a robust development plan for Mishrif in terms of well count, well and pads phasing, water injection distribution and voidage replacement management. This work led to 30% reduction in well count without impact on recovery factors.