Pre-Cenozoic-Recent basin modeling of the Timor Sea Region: implications for Petroleum Systems

Mateus da Costa a, Alejandro Escalona a, and Willy Fjeldskaar ab

a. Department of Petroleum Engineering, University of Stavanger, Norway
b. International Research Institute of Stavanger, Norway

Abstracts

Timor region is part of the Northwestern of Australian passive margin that is situated on the convergence zone between the Australian and the Eurasian Plate margins. Using subsurface data (3500 approximately Kilometers of 2D seismic data, 3 wells and previous studies) four different zones of deformation has been recognized: a) Zone 1 is characterized by Pre-Cenozoic age NW-SE and NE-SW trending rift basins situated on the Australian passive margin. Approximately about 6-8 kilometers thick of clastics and carbonate sediments were deposited during rift and syn-rift; b) Zone 2 is interpreted as a forebulge area situated between the Timor trench and Australian Passive margin. We interpret the forebulge as a flexural response to the bending of the thick Australian continental margin caused by loading of the Savu forearc basin and the Sunda Arc (both are part of Eurasian plate); 3) Zone 3 is characterized by Recent normal faults parallel to the Timor trench, mostly dipping north. This zone is located between the Timor accretionary prism and the forebulge area. We interpret this zone of extension as a response of flexural bending of the Australian plate in front of the subsudction zone; and 4) Zone 4 is characterized by the accretionary prism where the Timor Island outcrops. The prism is built of scraped-off sediments from the Australian continent and the nappes from the Sunda Arc since at least middle Miocene.
In order to understand the effects of the multiphase tectonic evolution in the Timor Sea and the effects on the petroleum system since the Mesozoic, we modeled two cross-sections using the BMTTM basin modeling tool that provided the geohistory, paleoheatflow and temperature history. The two cross sections were built using regional 2D seismic data that cross over the different deformation zones interpreted in the region, and are combined with limited data from wells such as vitrinite reflectance, temperatures, lithologic properties and facies distributions.