Sabriyah Lower Burgan Field EOR Development Study: Use of Sacrificial Wells to Minimize Water Encroachment

Abstract

Sabriyah Lower Burgan (SALB) is a multi-billion-barrel reservoir located in north Kuwait with favorable fluid and rock properties, and a strong active aquifer. The presence of the aquifer is advantageous for primary development of the reservoir but presents a challenge for conventional application of chemical EOR (CEOR). SALB has passed multiple stages of a CEOR evaluation process (technical screening, laboratory formulation design, SWCT, pilot design, risk assessment, etc.), and is currently considered for a multi-well CEOR pilot. This study investigates the viability of using sacrificial wells in the management of the lateral aquifer present in the SALB Layered formation, which represents a sought after CEOR target. The objective of these sacrificial wells is to reduce the potential negative impacts of the existing aquifer on commercial CEOR deployment. The adopted approach involved using a history matched field model with EOR parameters calibrated to laboratory results for ASP and CO2 technologies. The multi-well field model was used to evaluate and compare different development scenarios to assess the impact of sacrificial wells. These scenarios were evaluated based on production performance and economics. It was observed that strong aquifer presence complicates both CO2 and ASP project implementation. Challenges due to the aquifer include loss of EOR agents into the water leg, difficulty in accounting for effective pore volume of the project and water encroachment. It is difficult for EOR project economics to compete with an effective aquifer primary development. Sacrificial wells can be used to reduce the strength of the aquifer, potentially improving the effectiveness of the EOR technology. Although the sacrificial wells are unlikely to be economic on their own, they can improve the overall economics of the project. The amount of recovered oil due to EOR deployment is an important parameter to evaluate the economic feasibility of using sacrificial wells. Many reservoirs around the world have strong aquifers, for which conventional reservoir engineering advice has been to avoid EOR application. This paper introduces a novel approach to deal with these strong aquifers by strategically placing wells that can reduce the aquifer's strength, thus making EOR deployment more favorable.