Evaluation of the regional top seal in the Gippsland Basin: implications for geological carbon storage and hydrocarbon prospectivity
Louise Goldie Divko A , Geoffrey O’Brien A , Michael Harrison A and Joseph Hamilton BA GeoScience Victoria
B Ammtec Ltd
The APPEA Journal 50(1) 463-486 https://doi.org/10.1071/AJ09028
Published: 2010
Abstract
GeoScience Victoria and partners have undertaken the first detailed basin-wide study of the regional top seal in the Gippsland Basin. The Gippsland Basin is an attractive site for geological carbon storage (GCS) because of the close proximity to emission sources and the potential for large-scale storage projects. This top seal assessment involved the analysis of seal attributes (geometry, capacity and mineralogy) and empirical evidence for seal failure (soil gas geochemical anomalies, gas chimneys, hydrocarbon seepage and oil slicks). These datasets have been integrated to produce a qualitative evaluation of the containment potential for GCS, and also hydrocarbons, across the basin. Mineralogical analysis of the top seal has revealed that the Lakes Entrance Formation is principally a smectite-rich claystone. The geometry of the top seal is consistent with deposition in an early post-rift setting where marine sediments filled palaeo-topographic lows. The seal thickness and depth to seal base are greatest in the Central Deep and decrease toward the margins. There is a strong positive relationship between seal capacity column heights, seal thickness, depth to seal base and smectite content. At greater burial depths (below 700 m) and where smectite content is greater than 70%, seal capacity is increased (supportable column heights above 150 m). Natural hydrocarbon leakage and seepage onshore and offshore is correlated with fault distribution and areas of poor seal capacity. This study provides a framework for qualitatively evaluating seal potential at a basin scale. It has shown that the potential of the regional top seal over the Central Deep, Southern Terrace, central eastern Lake Wellington Depression and the southern to central near shore areas in the Seaspray Depression are most suitable for the containment of supercritical CO2. Further toward the margin of the regional seal in both onshore and offshore areas, containment of supercritical CO2 is less likely.
Louise Goldie Divko has BSc (hons), a DipEd and a PhD in geology. She has worked in both the education and petroleum sectors for Deakin University, the Victorian State Government and Schlumberger. Louise is employed as a geologist at GeoScience Victoria where her work focusses on the geological carbon storage potential and subsurface geology of Victoria’s sedimentary basins. Member: PESA Vic/Tas Branch, committee member. louise.goldie-divko@dpi.vic.gov.au |
Geoffrey O’Brien has a first-class honours degree and PhD in earth sciences. He has worked in the petroleum exploration sector for over 20 years. Geoff has worked for BHP, Western Mining Petroleum, AGSO/Geoscience Australia and the University of Adelaide and has consulted to a wide number of companies in Australia and overseas. He is the manager of the energy geoscience group at GeoScience Victoria. Dr O’Brien’s key technical specialities include the application of integrated petroleum systems approaches to basin evaluation, with an emphasis on basin and migration modelling (1D, 2D and 3D), charge history analysis, remote sensing, fault and top seal analysis and seismic interpretation of hydrocarbon leakage and seepage. Dr O’Brien has won numerous industry awards and was the 1992 PESA Australia Lecturer. He has also published over 170 papers and abstracts. geoff.o’brien@dpi.vic.gov.au |
Michael Harrison completed his BSc in 2003 and submitted his MSc in November 2008 at Monash University. His MSc project explored the tectonic development and structural evolution of the South Wanganui and northern Wairarapa basins, North Island, New Zealand. Michael is working as a petroleum geoscientist with the energy geoscience group at GeoScience Victoria. He has been working at GSV for the past three years and has focussed on evaluating the CO2 containment potential of the Gippsland Basin as part of the Victorian Geological Carbon Storage (VicGCS) initiative. Member: PESA Vic/Tas branch. michael.harrison@dpi.vic.gov.au |
Joseph Hamilton has BSc and DPhil degrees in geology from London and Oxford universities. He has held positions as divisional deputy chiefs and Australian Petroleum CRC Research Programme Manager for Exploration Technology while at CSIRO, and as Petroleum Geoscience Professor at the University of the West Indies. Since April 2009 he has been at AMMTEC as the technical leader for development and application of automated mineral analysis for the petroleum industry. His interests include isotope geochemistry, fluid inclusion microscopy, mineralogy and sedimentary petrography and their application to risk reduction in petroleum exploration and production. Member: PESA, FESAUS. Joseph.Hamilton@ammtec.com.au |
