Resolving lithostratigraphic complexities in the Crayfish Group, Otway Basin using chemostratigraphy

The Otway Basin comprises a significant part of the eastern Australian Southern Rift System, a divergent passive continental margin formed during the Cretaceous separation of the Australian and Antarctic continents. Early rifting activity resulted in the development of many half grabens within the Otway Basin, which are largely infilled by sediments of the Casterton Formation and Crayfish Group. Despite over 20 years of exploration and hydrocarbon production from these units however, their lithostratigraphic characterisation and nomenclature remain ambiguous, with structural complexity and prevalent lateral facies changes leading to confusion in their basin-wide correlation. Deposited in a largely non-marine, fluvial/lacustrine environment, repeating cycles of sandstones and shales of the Crayfish Group can be difficult to resolve using petrology, palynology and wireline log data. The use of chemostratigraphy is favoured as an investigative tool in this situation since changes in provenance, lithic composition, facies, weathering and diagenesis are reflected in the mineralogy of the sediments, resulting in variations in their inorganic geochemistry. Uniform sedimentary successions can thus potentially be differentiated into unique sequences and packages based on their characteristic geochemistry, aiding in the resolution of complex structural relationships and facies changes. In this study, we present new inorganic geochemistry data for four key wells in the South Australian (SA) Penola Trough and interpret the geochemistry data consistent with, and building on, the chemostratigraphic schema of Forbes et al. to demonstrate its utility and robustness. We then undertake inter-well wireline log correlations across the SA Penola Trough using the wells with chemostratigraphic data as controls.

Distribution and estimates of Australia's identified energy commodity resources

Australia is endowed with abundant, high-quality energy commodity resources, which provide reliable energy for domestic use and underpin our status as a major global energy provider. Australia has the world’s largest economic uranium resources, the third largest coal resources and substantial conventional and unconventional natural gas resources. Since 2015, Australia’s gas production has grown rapidly. This growth has been driven by a series of new liquefied natural gas (LNG) projects on the North West Shelf, together with established coal seam gas projects in Queensland. Results from Geoscience Australia’s 2021 edition of Australia’s energy commodity resources assessment highlight Australia’s endowment with abundant and widely distributed energy commodity resources. Knowledge of Australia’s existing and untapped energy resource potential provides industry and policy makers with a trusted source of data to compare and understand the value of these key energy commodities to domestic and world markets. A key component of Australia’s low emissions future will be the development of a hydrogen industry, with hydrogen being produced either through electrolysis of water using renewable energy resources (‘green’ hydrogen), or manufactured from natural gas or coal gasification, with carbon capture and storage of the co-produced carbon dioxide (‘blue’ hydrogen). Australia’s endowment with abundant natural gas resources will be a key enabler for our transition to a low emissions future through providing economically competitive feedstock for ‘blue’ hydrogen.

Green pivot: can Australia master the hydrogen trade?

Australia is in a bind. It is at the heart of the pivot to clean energy: it contains some of the world’s best solar irradiance and vast potential for large-scale carbon capture and storage; it showed the world the path forward with its stationary storage flexibility at the much vaunted Hornsdale power reserve facility; and it moved quickly to capitalise on low-carbon hydrogen production. Yet it remains one of the largest sources for carbon-intensive energy exports in the world. The extractive industries are still delivering thermal coal for power generation and metallurgical coal for carbon-intensive steel making in Asian markets. Even liquefied natural gas’s green credentials are being questioned. Are these two pathways compatible? The treasury and economy certainly benefit. But there is a huge opportunity to redress the source of those funds and jobs, while fulfilling the aspirations to reach net zero emissions by 2050. In our estimates, the low-carbon hydrogen economy could grow to become so substantial that 15% of all energy may be ultimately ‘carried’ by hydrogen by 2050. It is certainly needed to keep the world from breaching 2°C. Can Australia master the hydrogen trade? It is believed that it has a very good chance. Blessed with first-mover investment advantage, and tremendous solar and wind resourcing, Australia is already on a pathway to become a producer of green hydrogen below US$2/kg by 2030. How might it then construct a supply chain to compete in the international market with established trading partners and end users ready to renew old acquaintances? Its route is assessed to mastery of the hydrogen trade, analyse critical competitors for end use and compare costs with other exporters of hydrogen.

A new engagement approach for regulatory submissions

As a business strategy, Australian Gas Infrastructure Group (AGIG) has sought to leverage leading practices associated with stakeholder engagement to underpin the development of its submitted Access Arrangement Plan for 2021–2025 to the Economic Regulation Authority (ERA). The approach focused on developing a plan that would deliver for current and future customers and was capable of being accepted by all customers and stakeholders. The plan involved building an engagement model around six endorsed engagement principles that delivered a ‘no surprises’ outcome. This included active engagement with customers and stakeholders through a series of planned roundtables – commencing 14 months prior to formal submission. The process also included processes, structures and communication channels that supported group and one-on-one engagement and feedback sessions against a tightly managed timeline and the use of an online engagement platform. The extended abstract includes company representatives from AGIG and the stakeholder group (NewGen Power) reflecting on the process, engagement principles, leading practices adopted and lessons learnt through the engagement process.

Geological and Bioregional Assessments: a tale of two basins

The Australian Government’s $35.4 million Geological and Bioregional Assessment (GBA) Program is assessing the potential impacts of shale, tight and deep coal gas development on water and the environment in the Beetaloo, Isa and Cooper GBA regions. This paper compares the outcomes of impact assessments for the Beetaloo and Cooper GBA regions, highlighting the role that local geology, hydrogeology, ecology and regulatory regimes play when assessing potential impacts of unconventional gas development. Unconventional gas development activities between basins are broadly consistent, involving drilling, stimulation of the reservoir (typically through hydraulic fracturing), production and processing of hydrocarbons, export to market and decommissioning and rehabilitation. The characteristics of these activities and their potential impacts are strongly influenced by local factors including the geology, environment, industry practices and regulatory regimes. While subsurface impacts associated with hydraulic fracturing and well integrity are considered unlikely in both regions, regional geology means there is greater stratigraphic separation between target resources and overlying aquifers in the Beetaloo Sub-basin than in the Cooper Basin. Local ecological conditions and species influence the nature of potential impacts on protected matters in the two basins, which are mostly associated with surface disturbance and spills or accidental release of fluids. A key similarity between the two regions is the broadly consistent regulation and management of potential impacts in the two basins. Preliminary results of the causal network analysis indicate that mitigation measures are available for all pathways in which unconventional gas resource development activities may have the potential to impact on endpoints.

Effective engagement on process safety fundamentals in challenging times

Esso Australia Resources Pty Ltd (EAPL) and BHP Billiton Petroleum (Bass Strait) Pty Ltd own a range of offshore and onshore hydrocarbon production facilities, which have been operated by EAPL for over 50 years. Over this time, EAPL has lived a rich history of process safety experiences, and developed a range of processes and systems to manage process safety risks. Despite technical system refinement and advances across industry we continue to experience process safety events, and manage risks with plant both at the start and end of its lifecycle. Many of our major hazards are inherent to our operations, and do not become lower risk with lower product price or field activity levels. It is therefore critical that we maintain a laser focus on managing process safety risks during this time of unprecedented change, and find impactful opportunities to engage with operations, maintenance and technical teams on their role in process safety. To this end, EAPL have commenced a journey of scenario based process safety management and applying it to our most significant risks. The outcome has been a step change in process safety literacy across our business, an increased awareness of safe operating conditions and a workforce engaged in managing safeguard health. This study shares how a scenario based approach can leverage a traditional safety case and safety management system approach and make process safety personal: Simplifying communication of higher risks and the equipment and processes that keep us safe Clarifying safeguard ownership and responsibilities for safeguard health management Embedding safeguard health management in routine operations and maintenance tasks Strengthening critical safeguards which mostly depend on human performance to be effective

Top three LNG buyers to search for alternative LNG pricing structure after paying a total cost premium of $56 billion for oil-indexed LNG contracts in 2019 and 2020 – how will this affect Australia as the number one supplier to this market?

Increasing spreads between spot liquefied natural gas (LNG) and oil-indexed contracts have resulted in the world’s top three LNG buyers paying a cost premium of $33 billion in 2019 and 23 billion in 2020. The top three buyers are Japan, China and South Korea, which had a combined 151Mt of long-term LNG contracts indexed to oil in 2020. This cost premium shows what top Asian buyers are currently paying for the security of LNG supply through long-term oil-indexed contracts. However, it also shows the potential reward Asian buyers have if they manage to develop a liquid LNG pricing hub in Asia to which they can index their contracts. Japanese buyers’ efforts of increasing flexibility in contracts, both through take-or-pay agreements and destination flexibility and aims of growing the spot market, will increasingly support the liquidity of the LNG market. However, there will be resistance from the other side of the table, for where someone is paying a premium, or making a loss, someone is making money. 2020 was another year of plenty for LNG producers selling oil-indexed volumes to Asian markets. Australia is the largest seller of LNG to Japan, China and South Korea with over 60Mt of long-term LNG contracts indexed to oil in 2020. Australia has benefited from having their contracts indexed to oil, but what’s next? In this paper, Rystad Energy will discuss the future market for Australian LNG exports including development in LNG demand, contract trends and price spreads.

Using a satellite-aircraft hybrid system based on the same sensor to monitor oil and gas facilities for methane emissions

Monitoring methane emissions from oil and gas facilities requires the combination of several technologies to gain a full understanding of the challenge at a manageable cost. The integration of frequent and affordable high resolution satellite measurements to find the larger leaks with less frequent, but more expensive, aerial surveys, forms the basis of a tiered monitoring system showing great promise to optimise leak detection and repair activities. In this extended abstract, examples of methane emissions measurements from controlled releases and at oil and gas facilities acquired with both GHGSat’s second satellite, Iris (launched in September 2020) and the airborne variant of the same sensor are presented. While the combination of different technologies is not uncommon, this system is the first in the world utilising the same sensor at two different altitudes. The performance parameters of each system are highlighted and supported with recent examples. In addition, the advantages of the hybrid system will be discussed, including the opportunity for cross-validation of measurements. Finally, the potential of such a system to be used for regulatory reporting purposes will be discussed and contrasted to the standard of performing optical gas imaging camera campaigns three times a year used in some jurisdictions, notably in Canada and the United States.

Innovation and instrumentation in CO2 monitoring wells for reservoir surveillance and advanced diagnostics

In 2015, CO2CRC Ltd embarked on an ambitious plan to field test innovative technologies to monitor a CO2 plume injected into a saline aquifer with a view to address many of the economic and environmental concerns frequently associated with commercial carbon capture and storage project’s long-term monitoring programs (Jenkins et al. 2017). It was called the Otway Stage 3 Project and it was focused on testing the technologies of seismic and downhole pressures applied in unique ways to monitor an injected plume of approximately 15000 tonnes as it developed and migrated in the subsurface. To achieve this goal, five new wells were drilled at CO2CRC’s Otway International Test Centre – one dedicated to injection (drilled in 2017) and the remaining four wells (drilled in 2019) were used for monitoring purposes. Each monitoring well and the gas injection well, were outfitted with fibre optic systems installed and cemented outside the casing (specifically for seismic monitoring) and with pressure gauges installed at the reservoir depth. The challenge of the installation was to install fibre optics outside of the casing, cement them in place securely and to perforate the wells without damaging the fragile TEF bundles. While the installation of the pressure gauges in the injection well was a conventional in-tubing gauge mandrel, the installation in the monitoring wells, which were to be used for water injection as well as pressure monitoring, used a less conventional deployment method, where the gauges were instead installed using a more economic and flexible approach by suspending the gauges from the wellhead via a hanger system. This not only ensured continuous offline monitoring of the downhole well pressures and temperatures, but also facilitated future well operations by simple wireline retrieval and deployment of the gauge, forgoing the need for a workover rig. The various systems were commissioned over the period of March–June 2020 and were in full operation in the second half of 2020 – all successfully operating and acquiring baseline data remotely as designed. The Stage 3 Project commenced gas injection operations in December 2020 and data acquisition using the innovative systems have commenced successfully.

Geochemical evidence for a new Triassic petroleum system on the western margin of Australia

The unexpected discovery of oil in Triassic sedimentary rocks of the Phoenix South 1 well on Australia’s North West Shelf (NWS) has catalysed exploration interest in pre-Jurassic plays in the region. Subsequent neighbouring wells Roc 1–2, Phoenix South 2–3 and Dorado 1–3 drilled between 2015 and 2019 penetrated gas and/or oil columns, with the Dorado field containing one of the largest oil resources found in Australia in three decades. This study aims to understand the source of the oils and gases of the greater Phoenix area, Bedout Sub-basin using a multiparameter geochemical approach. Isotopic analyses combined with biomarker data confirm that these fluids represent a new Triassic petroleum system on the NWS unrelated to the Lower Triassic Hovea Member petroleum system of the Perth Basin. The Bedout Sub-basin fluids were generated from source rocks deposited in paralic environments with mixed type II/III kerogen, with lagoonal organofacies exhibiting excellent liquids potential. The Roc 1–2 gases and the Phoenix South 1 oil are likely sourced proximally by Lower–Middle Triassic TR10–TR15 sequences. Loss of gas within the Phoenix South 1 fluid due to potential trap breach has resulted in the formation of in-place oil. These discoveries are testament to new hydrocarbon plays within the Lower–Middle Triassic succession on the NWS.