b'AEGC 2023Short abstractsThe first phase of the EFTF programme (20162020) aimedDevonian rocks which vary between 18.0 to 30.0V-CDT to improve Australias desirability for industry investmentand 12.0 to 30V-SMOW, respectively. The sulphur isotopic in resource exploration of frontier regions across northernratio measured from H 2 S gas in the Montney reservoirs varies Australia. This paper will focus on the science impacts delivered,between 9.3 and 20.9V-CDT. Isotopic analyses suggest that by the acquisition of seismic surveys, petroleum geochemistrythe H 2 S generated from either Triassic sulphates or a mixture and the drilling of the NDI Carrara-1 drill hole. of Triassic and Devonian sources and not solely from Devonian The first seismic survey, L210 South Nicholson 2D Deep Crustalrocks as first expected. This research will be expanded to include Seismic Survey, was undertaken in 2017. It consisted of fiveother world-class unconventional reservoirs that show complex overlapping seismic lines (17GA-SN1 to SN5), totalling ~1100relationships between sweet and sour gas production.line-km and linked directly into legacy Geoscience Australia seismic lines 06GA-M1 and 06GA-M2. To complement thisRafael 1 - a tantalising gas-condensate discovery in the data across the underexplored and mostly undercover Southonshore Canning Basin.Nicholson and Barkly regions, a second seismic survey was undertaken in 2019. The L212 Barkly 2D Deep Crustal ReflectionKurt ChambersSeismic Survey, comprises five intersecting lines (19GA-B1 to B5), totalling ~813 line-km, extending from the NorthernThe Rafael 1 exploration well was drilled in the onshore Canning TerritoryQueensland border in the southeast, near Camooweal,Basin by Buru Energy as Operator of the EP 428 Joint Venture to the highly prospective Beetaloo Sub-basin in the northwest.with Origin Energy (50% interest) in late 2021 and made an The seismic programme was complimented by regionalexciting gas-condensate discovery in dolomites with anomalous geological studies, including the collection of geochemical datahydrogen peaks measured in shales of the Laurel Formation. and age dating, and led to the drilling of NDI Carrara 1. The well tested a significant four-way structural closure mapped on a sparse regional 2D seismic grid, although the stratigraphic The core result from the programme was the discovery of thesuccession at the well location was difficult to predict due to the prospective Carrara Sub-basin, interpreted to contain latelimited and distant well control.Paleoproterozoic to Mesoproterozoic rocks with strong affinities to the adjacent Mount Isa Province and Lawn Hill Platform. TheThere were several surprises and challenges that were multidisciplinary results include revisions to age constraints andcompounded by the remote operational conditions of the known stratigraphy of the mapped geological surface units foronshore Canning Basin. The significant uplift and erosion observed the region, as well as the identification of petroleum systemsat the Meda Unconformity in the Late Carboniferous in offset within the Carrara Sub-basin. A key outcome of the studies haswells is much less pronounced at the Rafael 1 location with the been an increased understanding of the resource potential forpreservation of a relatively complete Anderson to Laurel Formation northern Australia. sequence. Prior to drilling, the structure was thought to most likely be filled with oil primarily due to the Laurel Formation source rock being interpreted as absent in the flanking depocentres.Isotopic fingerprinting hydrogen sulphide (H2S) gas origins in unconventional reservoirs: The mitigation ofDespite the Canning Basin having a substantial endowment of tight gas resources, it is generally accepted that hydrocarbon environmental contamination in gas production columns will be small due to its complex structural history. Gareth Chalmers 1, Amanda Bustin2 and R. Marc Bustin2 However, Rafael 1 encountered a significantly over-pressured 165m gross gas column, with gas on rock pointing to a 1 The University of Sunshine Coastpotentially much larger column being present. Aligned with 2 The University of British Columbia the conference theme of breaking new ground, the Rafael 1 discovery has challenged a number of paradigms about the The distribution and origin of hydrogen sulphide (H 2 S) withinCanning Basin and supports the contention that significant unconventional reservoirs is of environmental concern due tovolumes of gas in conventional reservoirs are yet to be its high toxicity and ability to corrode metal infrastructure, evendiscovered despite sporadic exploration over the past 100 at extremely low concentrations (i.e., 50 ppm). The distributionyears. The well also confirms that opportunity hides where high of H 2 S, in some basins, can be inexplicable with a mix of sweetgeological complexity and sparse datasets intersect.(no H 2 S gas) and sour (contains H 2 S gas) wells within one multi-well pad. This warrants the building of a geological model to understand the H 2 S gas source, so that operators can deriskMonitoring the mobility of heavy metals and risk their drilling operations. assessment in mine-affected soils after stabilisation.The sulphur of the H 2 S is from multiple sources that includesJaeyoung Choisulphate minerals, oxidation of pyrite, organic sulphur within kerogen or sulphate ions within frack water. This research hasThe geophysical and geochemical analytical methods were utilised the isotopic variation in sulphur and oxygen coupledapplied to monitor the status of mine-affected soils after with X-RD and petrological analyses to determine the sourcestabilisation. The geophysical and geochemical methods of H 2 S gas. One case study for this international collaborationwere applied for stabilisation sites monitoring. ERI and IP were is investigating the Triassic Montney Formation in the westernevaluated for ASC and GB stabilisation sites. The main result of Canadian sedimentary basin. The Montney Formation canthis study is to explain the correlation of the IP response with produce H 2 S gas at concentrations between 0.001% (100 ppm)the stabiliser type and the concentration of heavy metals to the and 22% (220,000 ppm). Sulphate and oxygen isotopic ratioschanges in the stabilisation layer typically found at the stabiliser from sulphate minerals within the Triassic rocks range betweentreatment site. In general, the ERT and IP used in the evaluation 9.0 to 18.0V-CDT and -5.0 to 19.0V-SMOW, respectively.of the stabilisation treatment site showed the difference in These isotopic ratios differ from the sulphate minerals inthe electrical properties of the cover soil, stabilised soil and 87 PREVIEW FEBRUARY 2023'