Publications

Brunei Darussalam is located in the northwest part of Borneo, and overlies the Upper Miocene depocentre of the Northwest Borneo Basin. Sedimentation in this depocentre was dominated by shallow marine deposits, and the reservoirs consist of tidal and shoreface sequences. These facies are the main reservoirs of the existing giant fields in Brunei Darussalam. Detailed studies have been done to understand the Upper Miocene reservoir distribution in the eastern part of Brunei and how the structures control the sediment fairways.During the Upper Miocene, the sediments came from the northeast, sourced by the inboard Middle Miocene clastic series. The sediment pathways went to the accommodation space developed due to subsidence in the southwest of the studied area. These pathways were controlled by North-South trend structures, bounded to the east by a stable area and to the northwest by a counter regional fault. Progradational features were recognized from seismic. The well data indicate thickening stratigraphic unit towards the west but the net-togross ratio is decreasing. Significant increase of sediment thickness on the hanging-wall side of the normal faults indicates that the faults were active during deposition and generate additional? accommodation space.Following the deposition of the studied section, the eastern part was uplifted and the upper part of this section was eroded. A transgressive event followed, and a semi regional seal deposited.Recent integration of subsurface data and surface mapping works gave a better understanding of the depositional process. 3D seismic and well data were used for the offshore subsurface mapping. The onshore surface mapping utilizes SAR imaging and outcrop data.