Publications

The RG gas field development was started in 2014 to produce gas from Baturaja Formation limestones with three production wells. The field was only covered by 2D seismic and 3 (three) exploration wells. There was problem in water encroachment in one of production well. One new well was planned to replace, and the execution of this program required a revisiting study to ensure the optimum well location and gas production continuity as presented in this paper. This study covers the seismic interpretation, core description, sequence boundary, facies mapping, and static modeling. The Baturaja formation can be divided into smaller stratigraphic markers to reduce uncertainty on lateral facies distribution. Fortunately, the conventional cores were available to help in defining markers and describing the amount and distribution of the tight carbonates. The tight carbonates was then distributed using the isopach map which represented probability of tight facies. Parasequences were defined as stratigraphic markers are picked in 2D seismic. It was then followed by generating several depth structure maps for each zones. Facies probability maps were created from isopach maps facies probability for a static model purpose. Petrophysical analysis included the determination of dual porosity, cementation factor (m) determination and rock type-lithofacies interpretation. Final results of a whole integrated analysis are to establish an optimum water saturation and integrated lithofacies name of each rock type. Reservoir simulation has been run for history matching and prediction for new wells. The uncertainty in fault zones definition require several permeability fine-tuning to match production history. Propagation of permeability around the well that located close to faulted area controlled by pressure transient analysis result and also surveillance data. The study resulted in a more detailed structure and facies geometry. The reservoir simulation shows good history match. Several development scenarios were designed and one new well was proposed to maintain the gas production rate from the RG Field. This proposed well was resulted from the detail facies mapping and well placement design to encounter porous carbonate facies.