The Lower Miocene Great Barrier Reef of Sarawak, Malaysia: The Exploration Potential of Cycle II and III Carbonates

Abstract

A play-based exploration (PBE) study carried out in Shell assessed the remaining exploration potential of onshore and offshore Sarawak and enabled identification of sweetspots in previously overlooked plays, the definition of an internally consistent new lead portfolio, and the addition of a ranked list of coveted acreage (Gough et al., 2012). Furthermore, using PBE workflows, a framework was established connecting the evolution of tectonic regimes and basin fill with carbonate occurrences and growth styles since the Late Eocene and provided the basis for a play-based assessment of the remaining exploration potential of carbonate plays in Sarawak (Adams et al., 2012). The main carbonate play in Sarawak are the well known and intensively studied Middle Miocene to Pliocene Luconia Province carbonates. However, the above mentioned regional PBE study refocused Lower Miocene carbonates which in eastern Sarawak developed extensively. Both onshore and offshore, these ‘older’ carbonates have been penetrated by several wells including recent high profile discoveries. This paper puts forward the stratigraphic, tectonic, and age context of these Lower Miocene carbonates and examines the variability in carbonate deposition on the Sarawak Shelf. Finally, the remaining exploration potential is discussed by comparing and contrasting northern Central Luconia with south-eastern and onshore Sarawak.