Structural configuration and Cenozoic evolution of the deepwater offshore margin of Sabah, Borneo

The Sabah margin experienced a complex tectonic history during the Cenozoic, from the onset of the Paleogene South China Sea rifting to the late Miocene present-day compression. This work provides further insights on the tectonic evolution of the Cenozoic section, based on 3-D seismic interpretation covering the Sabah margin from the Dangerous Grounds to the Sabah Trough. In addition, by the means of sequential restorations to illustrate the geological evolution of the different parts of the Sabah margin, we established the sequence of events affecting the margin and their significance for the petroleum systems, mainly reservoirs/depositional environments, trap formation and integrity, and source rock maturation.

This work highlighted several new observations on this part of the margin, including the presence of mid-crustal detachments and possible exhumation of lower crust in places (in the Dangerous Grounds) associated to the rifting event, and the presence of compressional features in the distal part of the margin concurrent to the recent Sabah Fold and Thrust Belt, all of which may have an impact on the petroleum systems maturity and migration paths. Both the extensional and the compressional events contribute to structural trap formation and each of the identified tectonic episodes hold untested plays.