Publications

“Gardenia” field is located in Central Sumatra Basin was discovered in 1951. The field has reached its peak production of 11,700 BOPD in 1974 under primary depletion. Due to rapid pressure decline, the peripheral waterflood was commenced in 2005. Given ten years of oil production history with simultaneous water injection, the go-forward optimization strategy focuses on maximizing oil recovery through better reservoir management. This paper focuses on the application of integrated geological and engineering study on reservoir connectivity to improve waterflood performance and recovery. “Gardenia” field has a complex structural and stratigraphic framework, leading field compartmentalization. The initial injector and producer pairs did not adequately consider this complexity. Lack of integrated G&G and engineering analysis also led to unsuccessful of waterflood optimization. An increased understanding in stratigraphy has shown that flow of injection follows newly-defined flow units in this tidal-estuarine environment reservoir. The evaluation of reservoir engineering was done by using individual well data (spinner, pressure, and production data). Enhanced performance has been achieved by implementation of an integrated reservoir connectivity study. This reservoir connectivity study led to a more robust understanding of injector-producer alignment. Results have shown an increase of field by leading to an additional 4.6MMBO. Subsequently, an enhanced strategy for reservoir management, workover potential and optimization, and future infill horizontal well candidates for further field development can now be mapped. Diligent and creative integrated G&G study and engineering analysis provide an excellent alternative optimization strategy for “Gardenia” as a mature field. The extensive application of reservoir connectivity study appears to be a vital tool to economically extend the life of this mature field, maintain its production decline and achieve higher recovery.