Abstract
The Sabiriyah Mauddud limestone of North Kuwait is a super giant depletion drive oil reservoir. It is undergoing massive development efforts, with a planned enhancement in oil production through phased pattern water flood. The Phase1 development addresses the crestal area (50 km<sup>2</sup>) of the structure, which was the focus for development efforts in the past. The Phase2 development consists of all remaining peripheral acreage (200 km<sup>2</sup>), with immense reservoir rock & fluid uncertainties, leading to the identification of reservoir segments for re-appraisal through drilling & testing of new wells.
Re-appraisal work, along with enhanced fluid description, led to the conclusion that a large segment within the Ph2 area, originally considered as a regime of light oil - turned out to be viscous oil. This helped immensely the ongoing Full field dynamic modeling and development planning for this multi billion-barrel reservoir. This also led to the initiation of a Water flood pilot with Non-Conventional Wells in the poorer Ph2 area.
Two years of dynamic performance from producers and injectors located in the Ph1 area enhanced the understanding of the reservoir dynamics. Time lapsed monitoring of static reservoir pressures at key wells during the ongoing water flood, coupled with isochronal Pressure surveys during reservoir shut-downs and RFT data from newly drilled wells in the area during the post injection period, helped to confirm the pressure connectivity across the reservoir and the water flood response. Pressure transient and Production tests gave valuable insights into the well performance and reservoir architecture. In addition to monitoring and maintaining the Seawater injection system at high efficiency level, the regular program of water analysis at the pattern producers provided inferences on water breakthrough trend. Integration of the dynamic data with Production logs & FMIs led to the identification of speed zones with high permeability. This helped to fine tune the Static model.
This paper documents the case history of Waterflood management in a super giant carbonate reservoir and the challenges that had to be met.
