Bulletin of the Geological Society of Malaysia, Volume 36, Dec. 1994, pp. 145-156

Complex transtensional structures and the hydrocarbon potential of the Greater Sarawak Basin, Sarawak as defined by synthetic aperture radar

M.P.R. LIGHT¹, D.J. BIRD¹, G.A. POSEHN¹ AND M.A.A. HUDI²

¹Intera Information Technologies (Canada) Limited, Calgary, Alberta, Canada

²Petroliam Nasional Berhad (PETRONAS), Kuala Lumpur, Malaysia

Abstract: Synthetic Aperture Radar (SAR) is an active microwave sensor which operates both day and night and is capable of penetrating cloud cover and tropical haze. SAR has proved to be an excellent tool for mapping the critical structural elements of the Greater Sarawak Basin which strongly control the location and size of prospective hydrocarbon accumulations in East Malaysia. Interpretation of SAR data acquired for Petronas over the onshore part of the Greater Sarawak Basin combined with other geoscientific information has revealed the complex tectonostratigraphic history of the region. The high quality radar images are of primary use in exploration logistics, particularly in orienting and locating seismic acquisition programs and boreholes.

The West Sarawak Basin and the northeast part of the island of Borneo underwent complex transtensional deformation during the Tertiary related to strike-slip motion caused by the indentation of India against the Indochina-South East Asian block. These sinistral strike-slip zones are well developed as the Sabah Shear, the West Baram-Tinjar Lines and the Lupar Line-Paternoster Fault. Onshore extension of the seismically defined transverse faults in the South China Sea likely controlled the migration and accumulation of hydrocarbons in Sarawak. Thus SAR has been a critical tool in explaining existing hydrocarbon accumulations in Sarawak and delineating prospective regions.

The collision of the Australian continent with the Banda Arcs to the southeast and renewed subduction to the east and west put Borneo under compression in the Middle Miocene. Complex fold interference patterns produced by Cenozoic-aged strike-slip faults and the northward advance of the Rajang Accretionary Prism are well displayed on SAR data as are several suites of fracture lineaments corresponding to the prevailing stress regime. Lithological terrain units and structure defined in the SAR interpretation correlate well with documented field observations.

https://doi.org/10.7186/bgsm36199413