Cenozoic salt tectonics in the Officer Basin, Western Australia: implications for hydrocarbon exploration
Jane Cunneen A , Warwick Crowe A and Geoff Peters AInternational Geoscience
The APPEA Journal 54(1) 167-180 https://doi.org/10.1071/AJ13018
Published: 2014
Abstract
The Neoproterozoic western Officer Basin has a total sedimentary fill of up to 8 km and a depositional history with similarities to other central Australian basins, particularly the Amadeus Basin. The size and remoteness of the basin has traditionally been an impediment to exploration, and only sparse seismic and well data are available. In such areas, potential field data can be a powerful exploration tool to assess petroleum prospectively.
Salt distribution and mobilisation in the Officer Basin is poorly understood and has been significantly under-estimated due to a lack of quality seismic data. Examination of the existing aeromagnetic, gravity and seismic data, along with satellite and Shuttle Radar Topography Mission (SRTM) data, indicate that surface and shallow salt is abundant in the northern and central parts of the basin. Remobilisation of salt is greatest in the eastern part of the study area, decreasing towards the west, although the extent of salt occurrence to the west is unclear.
Salt diapirs occur along structural trends; east to west in the northeastern (Gibson) part of the basin, and northwest to southeast in the central (Yowalga) area. Neotectonic features such as surface lineaments and recent earthquake data suggest that minor tectonic reactivation is occurring in the present day, and is consistent with a present-day stress orientation of approximately 095°. Miocene to recent stress orientations suggest that structures in the Gibson area may have been reactivated as right lateral faults, whereas those in the Yowalga area are reactivated as left lateral faults.
Potential trap styles in the western Officer Basin include structural plays related to salt movement, such as drape folds, diaper overhangs, and thrusts. Late-stage movement of salt must, therefore, be considered when assessing the timing of migration pathways and possible seal breach. An improved understanding of the extent of salt in the Officer Basin, and the degree of reactivation during the Cenozoic, is vital for successful exploration in the region. Acquisition of high-resolution magnetic and gravity data would be a cost-effective exploration tool for better definition of salt and associated hydrocarbon traps.
Jane Cunneen received her BSc (Hons) degree in geology in 1997 and her PhD in structural geology in 2005, both from the University of Western Australia. She has worked in both the petroleum and minerals exploration industries, including in onshore and offshore basins in Australia, and also spent seven years with UNESCO developing the tsunami warning system for the Indian Ocean. In 2013 she joined International Geoscience as a senior geoscientist to work on hydrocarbon exploration projects in frontier basins. Member: PESA, and PESA WA Committee (2014–15). jcunneen@intergeo.com.au |
Warwick Crowe received his BSc (Hons) and MSc from the Australian National University, and his PhD from the University of Western Australia, and has more than 20 years’ experience in the integrated interpretation of geophysical datasets, structural analyses and exploration management. His diverse technical background includes work from prospect to province scales, in both mineral and petroleum targeted projects. Member: Society of Economic Geologists (SEG), Society for Geology Applied to Mineral Deposits, the Australian Institute of Geoscientists (AIG), PESA, and the Australian Society of Exploration Geophysicists (ASEG). wcrowe@intergeo.com.au |
Geoff Peters received his BSc (Hons) degree in geology and geophysics in 2001 from the University of Tasmania. He has a broad range of experience in geophysical techniques including three years spent modelling and interpreting data from the Falcon AGG gravity gradiometer system on both mineral and coal projects. Since joining International Geoscience in 2012, Geoff has been primarily involved with modelling and interpretation of potential field data including modelling of airborne magnetic, scalar gravity and gravity gradiometer systems. Member: ASEG. gpeters@intergeo.com.au |
