Incised valleys in marginal-lacustrine depositional environments: a new reservoir analogue from Lake Eyre, central Australia
Kathryn Amos A B , Carley Goodwin B and Angel Soria CA Australian School of Petroleum
B The University of Adelaide
C University of the Basque Country, Spain
The APPEA Journal 52(1) 513-524 https://doi.org/10.1071/AJ11040
Published: 2012
Abstract
Incised-valley fill deposits can form important hydrocarbon reservoirs and provide pathways for hydrocarbon migration. Incised-valleys formed in marginal-marine environments are well described, however, marginal-lacustrine incised-valleys have been the focus of extremely few investigations and are poorly understood. This paper provides a new description of incised-fluvial systems that are presently constructing terminal deposits in embayments around the shoreline of Lake Eyre, central Australia. It is anticipated that better awareness of such deposits will assist in the recognition of these depositional environments in the rock record, which should be useful for exploration purposes and for the generation of improved models for continental dryland fluvial-lacustrine reservoir deposits. A classification of all significant river mouth deposits around Lake Eyre (width >300 m; n = 104), from topographic map and satellite image data, found that 54% are incised-valleys presently accreting a terminal deposit in a shoreline embayment (playa lake estuary). The depositional elements of three incised-valley systems have been mapped using satellite imagery in a GIS platform, from which element geometries are described. Controls on incised-valley formation are investigated by comparing these observations with evidence for past lake highstands and neotectonics and observations from satellite images, geological map data, and digital elevation model data. The terminal splay deposits of rivers around Lake Eyre are well-used analogues for dryland reservoirs; however, the focus has been on deposits accreting directly onto the playa. It is likely the incised-valleys and terminal deposits in the embayments described here will be of interest to companies exploring in, and producing from, ancient drylands and other lacustrine depositional environments.
Kathryn Amos is a lecturer at the Australian School of Petroleum (ASP), University of Adelaide. She was awarded a PhD (2004) from the University of East Anglia, UK, and a BSc (environmental sciences) (hons) (1999) from the same university. Her first sedimentologic interest was for turbidity currents, on which her PhD and a one-year post-doctoral at the University of Leeds were focused. An experience with dryland fluvial sedimentology during her PhD drew her to Australia in 2005, to hold research positions at UNSW@ADFA and then the ASP (2007). She took on leadership of the Lake Eyre Basin Analogues Research Group industry consortium in 2008, and moved into a lectureship position in 2010. She continues to conduct research on Lake Eyre Basin analogues, as well as other sedimentologic and stratigraphic investigation of modern and ancient deposits from fluvial, marginal marine, and deepwater environments. Member: AAPG, SEPM, IAS, GSA. kathryn.amos@adelaide.edu.au |
Carley Goodwin received a BEng (Hons 2A) degree in Petroleum and Chemical Engineering from the University of Adelaide in 2011. Her Petroleum Engineering Honours research project was focused on incised-valleys around Desert Lakes, under the supervision of Kathryn Amos. Carley's Chemical Engineering Honours research project was on anaerobic digestion of marine microalgae for biomethane production. Carley was awarded the 2011 SPE Best Honours Presentation Prize and the 2011 Honours Project Prize for her Petroleum Engineering Honours project. While completing her Honours degree, Carley represented Australia in the 2011 Oceania Canoe Polo Championships. Member: SPE. carley.goodwin@y7mail.com |
Angel Soria received his B.Sc in Geography in 2003, and M.Sc in Physical Geography in 2006 from the University of the Basque Country, Spain. For his M.Sc thesis, Angel investigated the alluvial sediments of the Ebro River in northern Spain. He is, at present, finishing his PhD, focusing on the Quaternary evolution of the Ebro River in the Miranda de Ebro Basin. Angel is presently a lecturer in the Geography Department at the University of the Basque Country, Spain. Prior to this, Angel spent six months working as a research assistant on the Lake Eyre Basin Analgoues Research Group project in the Australian School of Petroleum, University of Adelaide. angel.soria@ehu.es |
