The presence of natural methane in Great Artesian Basin aquifers of the Surat Basin
K. Harris A , V. Pointon A and R. Morris AOrigin Energy.
The APPEA Journal 52(2) 674-674 https://doi.org/10.1071/AJ11088
Published: 2012
Abstract
The Surat Basin portion of the Great Artesian Basin (GAB) in Queensland has long been known to contain natural gas from both conventional and CSG sources. Commercial gas extraction from conventional sources target the Evergreen and Precipice Formations, which are among the lowermost of the Surat Basin stratigraphic units; however, evidence exists of methane occurrences in waterbores, which in most cases, access aquifers much shallower than recognised conventional gas or CSG targets.
Large-scale development of CSG in the Surat and southern Bowen basins has highlighted the presence of gas in aquifers overlying and underlying the coal measures. Potential issues associated with gas in waterbores include health and safety risks, and the difficulty of establishing baseline groundwater bore conditions against which potential CSG impacts can be compared.
Australia Pacific LNG has been investigating the presence of gas in the aquifers across the basin. The program has involved the routine measurement of wellhead gas concentrations and analysis of dissolved gas in waterbores. Stable isotope analysis of the dissolved methane (δ13C-methane and δD-methane) has been undertaken to ‘fingerprint’ aquifer gasses to ascertain their provenance. More recently, δ13C-CO2 has been added to the suite of isotopes. Initial results confirm the presence of natural methane across the study area and in all of the GAB aquifers sampled. Isotopic analysis indicates a distinct difference in isotopic signatures between the methane from the coal measures and that of the overlying aquifers from which most groundwater is extracted.
Kathryn Harris began her career in hydrogeology investigating salinity issues in the agricultural heartland of Tasmania. Moving to Brisbane provided the opportunity to move into a consulting firm with specialised groundwater capabilities, allowing her to work as part of a small, professional hydrogeology team delivering groundwater drilling and monitoring programs, groundwater supply assessments, and contaminated land investigations. She designed, implemented, and managed the groundwater monitoring program for the Airport Link Project and Northern Busway. Since 2010, she has been working in the petroleum industry at Origin Energy, specifically in the upstream business for CSG. She leads a small team, managing the baseline assessment program and researching aquifers of the Great Artesian Basin. She is a past president of the University of Tasmania Geology Club. She has had an academic paper published in Nexus and has co-authored a paper published in Hydrogeology in 2011. Member: IAH. |
Vair Pointon began her career working as a part-time assistant geologist at Toro Energy Pty Ltd, a small uranium exploration company in SA. During the four years there, she was involved in various projects in NT, WA, and SA. In between projects at Toro, she spent a summer working for Oz Minerals as an assistant mine geologist where she obtained mining experience in IOCG deposits. Shortly after this, she gained a part-time research position as a geoscientist at the Government of South Australia; major projects included researching the major orogenic events in the northern Flinders Ranges and assessing calcrete sampling techniques for uranium exploration in northern SA. She has recently moved to the petroleum industry as a graduate hydrogeologist at Origin Energy, working primarily in CSG, where she has been involved in various investigative projects about the Great Artesian Basin. Member: Aus IMM, International Association of Hydrogeologists (IAH), and Australian Institute of Geoscientists (AIG). |
Ryan Morris has worked in Australia, Europe, and southern Africa as a consultant and as a staff hydrogeologist. His experience includes groundwater resource management, impact assessment, supply, and monitoring. He has undertaken projects to assess the availability and sustainability of groundwater resources, assessed potential impacts associated with mining and infrastructure developments, and provided guidance (to clients) about monitoring and managing groundwater resource and the infrastructure. He is a senior hydrogeologist at Origin Energy, working mainly in the emergent CSG industry in Queensland. He is responsible for designing and implementing groundwater monitoring, aquifer injection, and subsidence monitoring programs of the Australia Pacific LNG project. He is a registered profession geoscientist (hydrogeologist) and is a recipient of the Australian Institute of Geoscientists WH Cundy Award. |
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