Innovative Pattern Balancing and Waterflood Optimization of a Super Giant Carbonate Mauddud Reservoir, Sabiriyah Field, North Kuwait

Abstract

Abstract Sabiriyah Mauddud (SA MA), a super giant depletion drive oil reservoir in North Kuwait (NK), is undergoing massive development efforts, with a planned enhancement in oil production through phased pattern waterflood. The Phase1 development covers the crestal area of the structure, which is the focus for current development efforts through 12 inverted 9-spot patterns. This paper outlines the successful integration of subsurface, water handling, well surveillance and production operations teams across the NK asset to significantly improve the operating procedure for waterflooding the SA MA reservoir. This effort required a new way of managing this reservoir in NK: a comprehensive approach of balancing voidage with injection, conducting extensive surveillance/analysis within the reservoir to assess the efficacy of various courses of action and, most significantly, adjusting various teams’ "key performance indicators" to align injection and production allowables with sound reservoir management principles. The health of the waterflood is regularly checked and monitored through revision of production/injection allowable and pattern balancing. An innovative unified information management system was used to monitor voidage replacement ratio (VRR) to provide a basis for pattern balancing. A very extensive surveillance operation provides the data necessary to monitor individual pattern balance and watercut performance, optimize areal sweep efficiency by adjusting injection and production allowables, assist in planning water shutoff operations, and design new completions. Time lapsed monitoring and the surveillance data indicates the reservoir is relatively well connected. Pattern VRR, pressures, and watercuts were somewhat out of balance prior to engaging in this effort. However, after applying the new management approach, individual waterflood pattern balance is significantly improved and the field-wide VRR is around 1.2. All of these activities have led to the enhanced understanding of the waterflood behavior and the model updates. Sound reservoir surveillance and waterflood management procedures implemented within a diverse group of teams that have performance goals aligned with "best practice" has resulted in effectively re-balancing this major waterflood. This effective integration of teams retains the flexibility to adjust for an ongoing development of this super giant field. This paper also brings out the case history of waterflood management in a super giant carbonate reservoir and the challenges met during the last seven years since the commissioning of the waterflood in year 2000.