Publications

Bekapai is a mature oil and gas field located offshore Mahakam delta and on production since 1974. The field has three lateral compartments, consisting of over 130 accumulations. Based on sequence stratigraphy analysis, the field is vertically divided into five zones (Shallow to Deep zone). Phase 1 redevelopment, completed in 2011 with the drilling of nine development wells, has not only successfully reshaped the field production, but also confirmed remaining potential of the Upper zone. This paper demonstrates a comprehensive evaluation of the Upper zone using two approaches, a deterministic evaluation using a drainage radius method, and dynamic evaluation comprising material balance and dynamic reservoir simulation. The drainage radius method, derived statistically and based on cumulative production of watered-out wells, has succeeded in locating un-swept hydrocarbon zones and estimating potential of future wells. A complete dynamic evaluation (material balance and reservoir simulation) was performed to strengthen the results of the deterministic evaluation. Consistent results between the two evaluations have been observed in term of ultimate recovery factor and also the future development’s incremental gain. This evaluation is critical as the Upper zone is projected to be the main contributor in the future field development, thus it defines the perimeters of the project, i.e. number of future wells, production forecast, etc. Keywords: Reservoir evaluation, drainage radius, material balance, reservoir simulation.