Topic Abstract : Source to sink analyses often focus on sediment supply pathways to the deep sea from an adjacent hinterland with far less emphasis on the intervening shallow marine environments that temporarily store sediment during its journey offshore. However, these shallow marine environments cannot be overlooked in NW Borneo because they were the sediment sink for a vast majority of the sediments in the up to 14 km thick middle Miocene and younger succession. Rapidly subsiding synclines, growth faults, inversion anticlines and shale ridges trapped sediment within several structurally-active sub-basins that were dominated by shallow marine environments. The evolving, structurally-generated topography changed the shoreline morphology frequently thereby segregating the shallow marine strata into thick, wave-dominant and tide-dominant successions and caused a quasi-independent stratigraphic succession to develop within each sub-basin. Several lines of evidence indicate that the sands with the best reservoir properties were deposited on wave-dominant, non-deltaic shorelines during transgressive events.
The evolving topography also continually modified the number and location of rivers reaching the palaeo-shoreline, resulting in a spatially and temporally variable sediment supply to the shelf edge. Seismic stratigraphic and fluvial outcrop observations indicate that there were multiple modest-sized rivers, of which the present-day Padas and Limbang appear to be the largest, longest-lived and most important with respect to sediment supply. The mineralogy and texture of the sand delivered by these rivers was diverse owing to contrasting bedrock lithologies in the different catchment areas; reservoir quality of the resulting deepwater sands is comparably diverse. Because of the multiple sources and frequently-changing sediment supply, the spatial and temporal distribution of deepwater sand accumulations are less related to sea level fluctuations than those sourced from a single shelf edge delta and also are smaller in size with a more scattered geographic and stratigraphic distribution. The complex sediment supply pathways and variable provenance appears to explain some of the stratigraphic and areal variability that occurs in the reservoirs of deepwater fields that are in close geographic proximity.
Speaker : Prof. Joe Lambiase, Program Director, Petroleum Geoscience Program, Chulalongkorn University
Dr. Joseph Lambiase received his A.B. in Geology from Brown University and his Ph.D. in Geology from McMaster University. After nearly 15 years as an international explorationist with Marathon Oil Company and Amerada Hess Ltd., Dr. Lambiase was appointed Brunei Shell Professor of Petroleum Geoscience and Head of the Petroleum Geoscience Department at Universiti Brunei Darussalam, where he was responsible for overseeing the growth of the department into an internationally-recognised centre for post-graduate petroleum geoscience education and research. In 2007, Dr. Lambiase established Lambiase Geoscience Pte. Ltd., a Singapore-based Petroleum Geology consultancy and since 2009 he has been the Program Director of the Petroleum Geoscience Program at Chulalongkorn University in Bangkok. He has published nearly 100 scientific papers and is a Past-President of the AAPG Asia-Pacific Region.
Venue : Corus Hotel KL, Ballroom 1 - Level 1
Doors open 5.45pm, Presentation starts at 6.30pm.
Sponsor : Halliburton