Publications

The Miocene Pendopo Formation has long been recognized as seal rock in the North Palembang Sub-basin of South Sumatra Basin. However, there exist sandstone interval within the Pendopo Formation that could possibly be a significant gas resource not previously evaluated.

This study aims to assess the sequence stratigraphy and reservoir potential of the Pendopo A (PEA) sandstone reservoir of the Pendopo Formation by integrating biostratigraphy, well logs, mud logs, and seismic reflection data. The focus is facies analysis, depositional environment interpretation on sequence stratigraphy perspective, reservoir modelling, and hydrocarbon resource assessment.

Low Quality Reservoir (LQR) “PEA” is typically a calcareous sandstone intercalated with thin carbonate layers which is interpreted as distributary mouth-bar and distributary channel deposits in the lower delta plain-delta front environment during the early Miocene Highstand System Tract (HST) which is supported by the presence of Geminilithela jafari nannofossil.PEA Sandstone has low petrophysical values: Vsh is 0.24-0.5%, PHIE is 0.04-0.11%, permeability is 0.02-36.9 mD, and SW is 0.28-0.77%. As supported by well test data, this reservoir has presence of non-combustible gas and oil shows. Seismic interpretation indicates the presence of northwest-southeast oriented anticlinal structures as potential hydrocarbon traps. Reservoir modelling reveals that Highstand LQR has facies that characterize the depositional environment in the lower delta plain and delta front areas, such as mouthbar sand, distributary channel sand, mudflate shale and delta front plateform shale. The LQR "PEA" is disadvantaged because of its low porosity and permeability , making the hydrocarbon extraction process more challenging but acidizing and fracturing may improve the reservoir properties and resources. Finally, the workflow and results presented in our study could also serve as an analogue for areas with similar geological settings, worldwide.