Publications

Tanjung Laban Field, located on the northeastern flank of the South Sumatra Basin, is one of 7 oil fields productive from Talang Akar Formation sandstones in the Corridor and Rimau contract areas. The discovery well, Tanjung Laban-1 , was drilled in 1982 by Asamera (South Sumatra) Ltd. on a seismically-defined structural closure on the upthrown side of the WNW-ESE trending Kluang-Iliran reverse fault.Since the discovery of the field, 23 development wells have been drilled. These wells confirm that the Talang Akar oil pool extends into Stanvacs Rimau PSC area. In accordance with government regulations, all hydrocarbons within the Talang Akar Formation were unitized under an agreement between Asamera and Stanvac.This paper discusses the reservoir geology of the Talang Akar sandstones in detail.The Asamera-Stanvac subsurface study indicates that the depositional systems of the Talang Akar sandstones can be divided into two energy regimes. A high energy flow regime produced clean, stacked, braided stream channel deposits. This regime was followed by a period of low energy, during which delta plain meandering stream deposits and interbedded coals were laid down. Several of the uppermost Talang Akar sandstones in this flood plain sequence have marine fauna and sedimentological characteristics which suggest that there was a tidal influence on the fluvial system. Dipmeter data, seismic isochrons and net sand isopach maps demonstrate that the dominant flow direction was toward the west - northwest and that the clastics were derived from the Tabuan basement high located to the east.Normal faulting juxtaposed different Talang Akar reservoirs resulting in a common oil/water contact (-874 meters) and an active water drive within the high energy, braided stream deposits. In the more lenticular lower delta plain and mouth bar deposits, oil/water contacts are variable and reservoir energy is dependent on a solution gas drive.