ABSTRACT: Commonality of petroleum systems in Southeast Asia Tertiary basins
Doust, Harry1, and Gerard Lijmbach2
(1) Shell International E&P, The Hague, Netherlands
(2) University of Technology, Delft, Netherlands
Most of the southeast Asian Tertiary basins have a similar geological development, which commences with graben formation, passes through phases of syn-rift fill and post-rift transgression, and ends with successive phases of deltaic regression. Time-wise, these phases typically span the Oligocene to Quaternary. This similarity of geological history is reflected in the range of lithofacies represented, which are common to the whole area and which can be closely correlated with depositional environments of proximal deltaic to distal deep marine origin. Those basins that were formed on the Asian continental platform ("Sundaland") are characterised by a dominance of more proximal environments and lithofacies, while those that are situated in less stable situations, such as eastern Indonesia and the Philippines, contain predominantly distal environments and lithofacies. In spite of sharing similar geological developments and range of lithofacies, the prospectivity of the basins is highly variable and very difficult to predict: This is mainly a consequence of the extremely short wavelength of environment and facies change. It is possible, however, to recognise that the petroleum systems represented in the basins have common characteristics, albeit variable in quality and development, and that they are shared across the area. They are: (i) An oil-prone syn-rift lacustrine source - deltaic reservoir petroleum system (mainly Oligocene to Early Miocene) (ii) An oil/gas-prone late syn-rift to early post-rift transgressive deltaic petroleum system (also Oligocene to Early Miocene), with mainly deltaic source and reservoir facies (iii) A gas-prone early post-rift petroleum system, sourced from and reservoired mainly in open marine carbonates (Early to mid-Miocene) (iv) An oil/gas-prone late post-rift regressive deltaic petroleum system, with deltaic source and reservoir facies (mid-Miocene to Pliocene).
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia