Top seal bypass risk due to fracture systems, nearshore/onshore Gippsland Basin
Bozkurt Ciftci A , Laurent Langhi A , Silvio Giger A , Julian Strand A , Louise Goldie-Divko B , John Miranda B and Geoffrey O’Brien BA CSIRO
B Victorian Department of Primary Industries
The APPEA Journal 52(1) 397-414 https://doi.org/10.1071/AJ11032
Published: 2012
Abstract
The extensional architecture of the Gippsland Basin was modified by a phase of contractional deformation during the Oligocene—Pleistocene postdating the main subsidence phase of the basin. This deformation caused local inversion and folding, which modified the depocentre geometry and controlled deformation of the syn-kinematic regional top-seal—the Lakes Entrance Formation. Accordingly, there is spatial variation of deformation intensity and lithofacies distribution, the latter of which possibly affected the strain accommodation behaviour of the Lakes Entrance Formation. These factors are critical and locally detrimental to seal capacity.
In this study, the volume of shale distribution of the Lakes Entrance Formation was modelled and various parameters of the seismic-scale faults were computed, including shale gouge ratio, slip tendency and dilation tendency. Sub-seismic deformation was captured by strain and curvature attributes at the Latrobe unconformity, which carries the most intense imprint of the deformation phase. These parameters were correlated to known hydrocarbon seepage and leakage indicators in the basin, which could be related either to: (i) localised deformation along fault zones; or, (ii) to distributed deformation separated from the fault zones. There is generally a good match between the anomalous values of the computed parameters and the location of leakage indicators. For fault-related localised deformation zones, the match of the parameters ranks in the following order: shale gouge ratio (95%), strain (84%), curvature (84%) and slip tendency (74%). By combining these four parameters, a fault-related leakage assessment factor (FLAF) was defined and mapped across the study area. Match ratio of the parameters used to capture distributed deformation separated from the fault zones are ranked in the following order: curvature (100%), strain (100%) and volume of shale (83%). These parameters were also combined to define an ‘other’ leakages assessment factor (OLAF) and mapped across the study area. FLAF and OLAF maps are consistent with known leakage/seepage indicators in the basin and are indicative of additional areas with potential risk for top seal bypass. These risk maps provide useful input to CO2 storage and hydrocarbon exploration efforts in the basin.
Bozkurt Ciftci is a senior research scientist at CSIRO. He holds a MSc in petroleum geology (2001) from Colorado School of Mines and a PhD in structural geology (2007) from Middle East Technical University. Before joining CSIRO as a senior researcher in 2008, he worked as an exploration geoscientist for seven years at Turkish Petroleum Corporation and a led number of exploration projects across eastern Mediterranean and Aegean regions. His present focus at CSIRO includes reservoir to semi-regional scale structural analysis and fault seal assessments relevant to exploration and production of hydrocarbons and geological storage of CO2. Bozkurt.Ciftci@csiro.au |
Laurent Langhi is a senior research scientist and research team leader with CSIRO Earth Science and Resource Engineering and has 10 years of experience in petroleum geology and exploration geophysics. After earning an MSc and PhD in geology, he worked as a researcher at UWA and as an exploration geologist/geophysicist in the oil and gas industry. In 2006, he joined CSIRO Petroleum, focusing on structural geology, trap integrity prediction, assessment/visualisation of fluids migration, and geomechanical modelling. He also works in the fields of seismic attributes analysis, and quantitative seismic for conventional hydrocarbon and CCS. Laurent.Langhi@csiro.au |
Silvio Giger holds a MSc in structural geology from the Swiss Federal Institute of Technology (ETH) in Zurich and a PhD in rock deformation from ANU in Canberra. Between 2007 and 2011 he held the position of a research officer at CSIRO in Perth, where he was mainly involved in experimental fault seal research. Silvio is now a project manager in geology at Nagra in Switzerland. Silvio.Giger@nagra.ch |
Julian Strand is a senior research scientist at CSIRO Earth Science and Resource Engineering, primarily working on structural geology and issues related to incorporating structural geology into reservoir and basin models. Julian has been based in Perth since 2005 and was part of the Fault Analysis Group for nine years at the University of Liverpool and latterly UCD in Ireland. He attended the University of Liverpool and Imperial College, London. Member: AAGP and EAGE. Julian.Strand@csiro.au |
Dr Louise Goldie-Divko has an Honours degree in science, a Diploma of Education 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 now employed as a geologist and project manager at the Department of Primary Industries, where her work focuses on the geological carbon storage potential and subsurface geology of Victoria’s sedimentary basins. She is also the present PESA Vic/Tas Branch President. Louise.Goldie-Divko@dpi.vic.gov.au |
John Miranda graduated in 2002 from the School of Earth Sciences, University of Melbourne, with a BSc (Honours) in geology, with his honours research focusing on the sedimentary evolution of Victorian phosphate deposits. He obtained his PhD in 2007—also from the University of Melbourne—where he conducted research on the Neogene basin evolution and sedimentology of the Murray Basin. He is now employed as a geoscientist/basin analyst at Geoscience Victoria, working on the carbon storage potential of the Gippsland Basin as well as unconventional hydrocarbon potential across the state. john.miranda@dpi.vic.gov.au |
Dr 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 also consulted to a wide number of companies in Australia and overseas. He is now 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 |
