Water Injection Optimization for Natural Fractured Carbonate Reservoir: Descriptive Model Configuration Achieving Optimized Field Management: Khepri-D Field Case

Abstract Development of naturally fractured reservoirs, and water flooding pattern design for such reservoir is critical due to complicated nature of this type. The objective here, was how to maximize oil production and reserves through minimizing early breakthrough risk at the producers and define the optimal locations of new producers and injectors. In moderate development stages, the degree of confidence increased in static model including fracture network, permeability. facies and dynamic data (ex. production data) is relatively high. A reservoir simulation study of the depletion drive oil mechanism in (Khepri-D field), was done to evaluate its original oil in place (OOIP), recovery factor (RF) and hence the optimum Field Development Plan (FDP) and injection pattern. Integration between reservoir, geological and petrophysical teams was organized to achieve this target. Reservoir study passed through different phases of history matching, along the reservoir lifetime. First history matching phase, was after one year of discovery and the second phase was after three years. In primary phase, the main concern was the pressure matching, which should be consistent with rate transient analysis and material balance rather than the water breakthrough. Consequently, building scenarios to describe static model, mainly includes representation of fracture network and geological structure of high productivity wells. Appropriate changes in structure model have been done to eliminate chance of early breakthrough. In the second phase, the main objective of the study was evaluation of proposed development injection and production wells. The preferred locations of wells would achieve maximum impact on the economics without losing reserves. The model uncertainties have been reduced by conducting several scenarios, especially on the structure model. Finally, there were two scopes of results for the two phases of study. The first Phase, the study proved that current structure will not be representative and need to be reconfigured for achieving accurate history matching, in order to be consistent with reservoir management work, especially OOIP, that was estimated from reservoir analytical method. Drilling new wells was mandatory to confirm and capture additional reserves. as per the second phase of the study, dynamic modeling resulted in drilling a new well with initial oil production rate around 5000 STB/D. The proposal of new drilling opportunity, based on the structure configuration, facies, SCAL analysis, and fracture network achieving high ultimate recovery of about 40%. This paper is a good example of how to develop depleted carbonate reservoirs achieving reasonable ultimate recovery through cooperative work between all disciplines and gathering data from different source to build integrated representative model.