Bulletin of the Geological Society of Malaysia, Vol 47, Dec. 2003, pp. 85-94
EPD-XDW, Sarawak Shell Berhad, 98009, Lutong, Miri, Sarawak
Abstract: Key risks for exploration in deep-water Neogene basins are reservoir development, hydrocarbon charge and trap retention. Over the last two years SMEP‘s deep water asset team, EPD-XDW, has made a concerted effort to de-risk the NW Sabah deep water prospect portfolio through large-scale 3D seismic acquisition, integrated basin analysis studies, green-field exploration and deep-water field appraisal. This evaluation allows the main Miocene turbidite fan systems of the Sabah trough to be slowly unraveled and will establish NW Sabah as a classic area for the study of active margin deep-water sedimentation.
The NW Sabah basin has a surprisingly rich sand fairway, with at least four fan depositional cycles being recognised within the Upper Miocene stratigraphy between 12.1 and 6.7 Tertiary boundaries, TB2.6-TB3.3. The thickest and best known fans are those of the Kebabangan, Kinarut and Kamunsu, all named after the wells which discovered them.
The Pink fan is the last of the sand-prone Upper Miocene fans deposited in the Kamunsu basin and was deposited the furthest outboard, partly in response to the progradation of the shelf edge across the Sabah margin and partly due to local tectonics which strongly influenced the contemporaneous sea-floor profile. The older fan units within this basin are all disconnected from their slope feeders by faulting and erosion. In the past, this hindered reservoir prediction and the generation of viable palaeogeographical reconstructions. The Pink fan is still connected to its feeder canyon and, best of all, has been drilled twice in recent years. This well data in combination with detailed seismic evaluation has enabled the unraveling of this confined fan unit to a degree not yet achievable within the older fans.