Publications

SNA Field is a highly productive PT. Pertamina EP Java Region oil field located in Northwest Java Basin. SNA Field has cumulative oil production of 9.986 MMSTB, condensate 616.952 MMSTB and 37.694 BSCF gas. Middle Miocene Mid-main Carbonate (MMC) build-up in the Cibulakan Formation is the primary producing reservoir in SNA field. The SNA MMC build-up was deposited on restricted up to open marine carbonate shelf. From the combination of well log, seismic and mud log data, the facies are mudstone-wackestone facies and boundstone facies. These interbedded rocks were formed during several build-up development stages. The shales are mainly terrigenous non-carbonate development stage. High resolution wireline logs and seismic data show several transgressive-regressive cycles. Through sequence stratigraphic approach from wireline logs, it was determined that the SNA MMC build-up was deposited in LST (Lowstand System Tract) phase. To determine the shape of the carbonate in its early growth stage, a sequence boundary flattening was needed, in which the sequence boundary itself is located below the carbonate. From this correlation, a depositional model was made, and it shows the diagenesis process that occured in the SNA MMC build-up related to sub-areal exposure. The diagenesis process resulted in high porosity development in this reservoir. The analysis is supported by petrophisical data of each exposure area, and it shows high porosity percentage, with porosities ranging from 11% to 21%. This study looks closely at a prolific hydrocarbon producing aggrading carbonate build-up reservoir * University of Padjadjaran along with the determination of sub-areal exposure and the implication for hydrocarbon prospect and development. Keywords: Depositional model, mid-main carbonate, Cibulakan Formation, carbonate reservoir