Geoffrey William O'Brien1, M. Webster1, G. Lawrence2, A. Williams3
(1) Australian Geological Survey Organisation, Canberra, ACT, Australia
(2) TREICOL Limited, Knebworth, Hertfordshire, United Kingdom
(3) Nigel Press & Associates, Crockham Park, Edenbridge, Kent, United Kingdom
ABSTRACT: Interpreting Hydrocarbon Migration and Seepage in the Timor Sea and Browse Basin, North-Western Australia: An Example of Data Management and Integration Within a GIS Environment
Hydrocarbon migration and seepage in the Timor Sea and northern Browse Basin have been studied using multiple remote sensing technologies over an area exceeding 365,000 square km and extending from the coastline to abyssal water depths. 55 RadarSat Synthetic Aperture Radar (SAR) satellite scenes, 18,000 km of geochemical sniffer, and over 30,000 km of reprocessed Mark II and III Airborne Laser Fluorosensor (ALF) data were analysed. The interpretations derived from these independent seepage detection technologies have been compared and contrasted, and then integrated with an extensive petroleum geological data-set, including seismic data, field (breached and commercial) distribution, oil family work, isopachs of key source and sealing units, and Neogene (reactivation)and Jurassic (rift) fault maps. This iterative approach, which was completely managed within a GIS environment, has led to a new appreciation of the key controls on secondary and tertiary migration, and seepage processes, over the entire region.
In the Timor Sea, where Neogene fault reactivation and attendant fault seal failure represent significant risks, migration indicators tend to be controlled by a combination of lateral migration from source depocentres, and localised vertical migration, associated with fault tip stresses, and Neogene faults. In contrast, in the Browse Basin, migration indicators are principally controlled by long-distance lateral migration from source depocentres and seepage at the edges of regional seals; seepage along fault systems tends to be minor. These results provide an interpretative framework for assessing migration, charge history and top and fault seal integrity at scales ranging from regional to prospect-specific.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado