Print this pageStructural Style, Petroleum System and Exploration Challenges of the Ne Sabah Basin, Sabah (North Borneo), Malaysia
The NE Sabah Basin has undergone a complex tectonic history from the Lower Miocene to Upper Pliocene. Tectonic phases involved periods of extension, compression inversion and transpressional strike-slip faulting. Five sequence boundaries are interpreted in the basin which defined four megasequences as fore-arc setting, syn-rift, post-rift and post-inversion.
Major folding, uplift and associated faulting occurred during the Late Miocene. Strong transpression rejuvenated many existing faults and created faulted-anticlinal structural highs. Following this the deposition of transgressive sequence continued. Deformation continued from Pliocene to present with major strike-slip faulting and transpressional movement. Structural style is represented by multi-directional, extensional normal block faulting and growth faulting overprinted by multiple stages of compressional through transpressional deformations.
The area is characterized by the presence of several structural features within three regionally dominant trends which form the structural play types. Within these only a few small hydrocarbon pools have been discovered to date. An active petroleum system is demonstrated in the basin. However, major risks are source, migration path ways, fault sealing and fault reactivation. Hydrocarbons accumulation occurs throughout the Middle Miocene deltaic to shallow marine sections. The major troughs within the vicinity of the structure to the north and south are the main source of the hydrocarbon that generated in the basin. Source rocks are made up of mainly dispersed terrestrial organic matter mostly coals and organic rich shales originated from fluvio-deltaic and paralic depositional system. Due to coaly nature of the source rocks, they are dominantly gas-prone. The amount and quality of source rock presence in the surrounding area of the structure could be a critical factor. The top seals are expected to be provided by the intraformational transgressive shales.
There are three main play-types observed. The deltaic plays in the northern area were tested by several wells with minor gas and oil discoveries. Several carbonate plays may exist and penetrated by several wells in the southern margin. Deepwater turbidite plays are penetrated in several wells in the eastern part.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil