The worldwide intent to urgently mitigate climate change underscores the significance of CCS. However, to date, there is a major deficit in ready, or under development, commercially viable, CO₂ geological storage (CGS) resources. 

Realising the much-espoused potential of CCS requires more effective use of known CGS resources, and pursuit of sub-optimal CGS prospects. This is of particular importance for maximising CGS hubs and providing proximal CGS resources for hard-to-abate sectors. Further, technical solutions are required to address the uncertainty in the prediction of behaviour and long-term fate of the injected CO₂, to hasten resource development, safely approach reservoir technical limits, and enable effective site closure. CO2CRC, in collaboration with international partners, is actively addressing this challenge through the Otway Stage 4 Program.

Otway 4 aims to develop and demonstrate a suite of reservoir management strategies and solutions, that result in cost-effective CO₂ storage optimisation techniques, and to mature these for commercial readiness. New infrastructure is currently being installed at CO2CRC’s Otway International Test Centre to achieve this, including new bores and the CRC-8 monitoring well. From 2024, a series of CO₂ injection and monitoring operations will take place, to provide essential high-resolution data to achieve the Otway Stage 4’s storage optimisation objectives. 

This storage optimisation field R&D program comprises four key elements:

1.       Characterisation of Fine-Scale Heterogeneity and Fault Impact: Gain a deep understanding of how fine-scale heterogeneity and faults influence CO₂ distribution. The GeoCquest Field Validation (GFV) Project and Otway Shallow Fault Project are vital for this element.

2.       Innovative Performance Monitoring Techniques: Develop and test innovative monitoring techniques tailored to evaluate injection and storage performance. The innovative Distributed Strain Sensing (DSS) technique and the Seismic Monitoring Project, applied to all Otway Stage 4 injections, are the key monitoring techniques for this element. 

3.       Enhanced Injection Techniques: Develop and test novel injection techniques designed to improve CO₂ storage sweep efficiency and enhance trapping. Activities include the Microbubble Injection Project and the Surfactant Project. 

4.       Advanced Reservoir Modelling: Advance the capability to comprehensively model CO₂ behaviour and reservoir response to thermal, hydrological, geomechanical and geochemical changes. This includes the integration of the new monitoring data to conform models and the development of the capability to simulate the effects of the newly devised injection techniques.

This presentation forms the basis for several Otway Stage 4 presentations in the symposium, which delve into laboratory and modelling work to date, as well as forward R&D plans that will stem from the CO₂ injection operations commencing next year.

The GeoCquest Field Validation (GFV) project will for the first time monitor the migration of a CO₂ plume through an observation well where gas saturation will be measured using high-resolution pulse neutron logging. CO₂ plume migration and trapping will be predicted pre-injection and post-injection using the observational data. The project is part of CO2CRC’s Stage 4 Program and involves researchers from The University of Melbourne and Stanford University (USA).

The prediction of CO₂ migration has been shown to be notoriously difficult particularly in heterogeneous reservoirs due to the uncertainty in rock type distribution and sub-metre scale heterogeneity. The latter is not accounted for in conventional grid cells which are often at a scale of 10s of meter in horizontal and several meters in vertical direction. A number of different geo-models have been developed for the Paaratte Sequence 2 at the IOTC. These models are based on different modelling approaches (object-based, sequential indicator simulation), differ in grid cell sizes and partly include composite rock types and their properties accounting for small-scale heterogeneity. The different geo-models are the framework for the simulation of CO₂ migration and trapping leading to large differences in the CO2 migration behaviour. We expect models with small grid cell sizes and composite rock types will predict CO₂ migration more accurately, however, the model domain requires to be relatively small due to the large number of grid cells. Ultimately, the comparison to the GFV field experimental results will indicate which type of model is most suitable for modelling the migration of CO₂ in heterogeneous reservoirs.     

Carbon Capture and Storage (CCS) plays a vital role in climate change mitigation, yet enhancing CO₂ injectivity into geological formations remains challenging. This presentation examines the potential of surfactants in addressing this issue. It starts with the initial hypothesis that surfactants can lower interfacial tension and modify wettability between CO₂, brine, and rock, thereby affecting CO₂ injectivity. Both experimental evidence and numerical simulations lend credence to these assumptions.

The research adopts a multi-scale and multi-methodological framework. We evaluate various surfactants for their capacity to reduce interfacial tension and modify wettability. The work extends to multi-scale flow experiments, embracing advanced techniques ranging from pore-scale analyses using synchrotron light source X-ray scanners and microfluidic chips to core-scale CO₂ relative permeability assessments. Our findings suggest that surfactants can potentially enhance CO₂ saturation and relative permeability, with some experiments showing a twofold increase in relative permeability compared to the baseline.

Towards the end, the presentation will touch on initial plans to explore the feasibility of surfactant-aided CO₂ injectivity at the Otway International Test Centre (OITC).

The Otway Shallow Fault Project is a field demonstration that aims to better understand CO₂ migration in faults, by injecting a small amount of CO₂ into a shallow fault under highly controlled conditions to image the CO₂ migration behaviour and reservoir response. This experiment enables critical capabilities in the accurate representation of fluid flow in shallow faults to be developed and transferred to deeper faults.

The previous appraisal work answered key questions regarding the rock-fluid mechanics, subsurface structure through seismic and rock coring and groundwater quality. Numerical simulations of potential CO₂ were completed to assess the pathways and behaviour of the plume during and after the injection. Two bore holes, Brumbys-1 and Brumbys-2 were drilled in the previous phase to underpin the appraisal phase.

In preparation for the operation phase, where CO₂ injection operation occurs, two new boreholes Brumbys-3 and 4 are drilled. The wells are completed with fibre optics and pressure gauges outside the casing. A gravel pack is installed at the targeted injection interval of ~65 – 75 m depth in the injection well. Both wells are armed with fibre optics cables to record Distributed Acoustic (DAS), Temperature (DTS) and Strain (DSS) sensing. 

The experiment would provide an opportunity to demonstrate high-resolution, semi-continuous, combined reverse Vertical Seismic Profile (VSP) and Distributed Strain Sensing (DSS) monitoring of CO2 movement near and along a fault. In preparation for the injection phase in Q1 of 2024, a water pump test was completed to understand the injectivity of the injection well (Brumbys-3), pressure and hydraulic communication between the wells and to update the reservoir model with the collected data.

The behaviour of a small amount of gaseous CO2 is different from the larger plume in the dense phase. Significant efforts were dedicated to modelling the likely behaviour of the CO₂ plume around the Brumbys fault. The previous forward-modelled scenarios are updated with the outcome of the water injection test. Parallels are also drawn from experimental sand box models of the injection scenario to demonstrate the likely behaviour of the CO₂ during and after injection. The findings of the updated models are key in adjusting the planned monitoring solutions to enable effective imagining and detection of the injected CO₂.

A key question for the Otway Fault Project is what happens to the CO2 when it reaches the upper clay layer after migrating up Brumbys Fault? The Hesse Clay sits as a 2m thick blanket over the Port Campbell Limestone and Brumbys Fault. Permeability tests on clay core suggests the clay has very low permeability. Further, groundwater monitoring wells Brumbys 1 and Brumbys 2 are artesian (i.e. the ground water level in the wells is above the ground surface) during the high rainfall wintertime, suggesting a level of confinement. 

Shallow groundwater monitoring over a 4-year period has provided further insight into the permeability of the clay. Evidence from groundwater level response times after rainfall events and barometric response functions suggest the clay is semi-permeable. This suggests that if the controlled release experiment is conducted during dry conditions, it is likely that the CO2 gas will find leakage pathways through the clay and reach the surface above the fault zone. Surface soil flux monitoring will be employed during the experiment to assess this anticipated CO2 migration behaviour.  

Objectives and Scopes
For CO₂ geologic storage projects, faults present potential leakage risks. To better understand fluid flow behavior in and around faults, a shallow CO₂ controlled release field project will be conducted at the CO2CRC Otway International Test Centre by injecting into the Brumbys Fault. In order to de-risk the field project, in this study we conducted several sand tank experiments to model and validate field-scale simulation results prior to project commencement. 

Methods, Procedures, and Process
CO₂ will be injected at 60m below ground near the fault zone of the shallow Brumbys Fault. To replicate the field geologic pattern in the lab setting, we mixed different grain sizes of glass beads so that their capillary entry pressure ratios are equivalent to the permeability ratios measured for the various layers. We then manually packed the sand tank domain according to a 2D cross-section from the field-scale simulation domain shrunk to the size of the tank. Finally, we conducted buoyancy-driven fluid flow experiments at ambient conditions using different analog fluids and compared the results with field-scale simulations. 

Results, Observations, Conclusions
According to the results of the air/water experiments, once air (representing gaseous CO₂) enters the high-permeability fault, it rapidly migrates upward due to high buoyancy forces and accumulates underneath the capping clay layer. Therefore, the highest CO₂ saturation is expected to occur near the top of the fault, consistent with the field-scale simulation results. Even when the injection point is moved farther away from the fault, there is still a high chance that the injected gas would enter into the fault zone. Further experiments with a different analog fluid pair (Soltrol 220/glycerol-water mixture) have demonstrated that the fault leakage behavior is likely to be similar even when occurring at depth where CO₂ is a supercritical fluid. 

Significance/Novelty
Fault leakage is just one area of concern for CO₂ storage projects, and sand tank experiments provide a low-cost, visual, and dynamic way to validate field-scale simulation results before the projects start, hence boosting confidence and reducing risk. The sand tank experimental methods can also be applied to study various other aspects of CO₂ storage such as how heterogeneities, dip angles, and injection scenarios affect plume spread and stabilization, helping to further de-risk CO₂ geologic storage. 

The Shallow Fault Project aims to investigate the movement of CO₂ injection along and/or through the fault plane in the Port Campbell limestone reservoir. Significant efforts were dedicated to modelling the likely behaviour of the CO₂ plume around the Brumbys fault. In preparation for the injection phase in Q1 of 2024, a water pump test was completed to understand the injectivity of the injection well (Brumbys-3), pressure and hydraulic communication between the wells and to update the reservoir model with the collected data.

The pump test, completed in August 2023, provides valuable data on reservoir performance and injectivity.  Two wells, Brumbys-1 and Brumbys-3 were utilised for the injection and all four bores collected pressure, temperature and strain data during the test. Brumbys-1 is in communication with the formation through the screened interval at 98-110m, where it intersects the Brumbys fault. The screened interval of Brumbys-3 is open at 69-79m where the intended 10 tonne injection is to happen.

Visual checks through downhole camera showed that majority of the screened interval is covered by debris, hence potentially impacting the injectivity during the CO₂ injection operation. Well cleaning was performed prior and in-between the water test intervals and its impact was assessed against the injectivity performance.

The water injection adopted variable rates (50 litres/min to 150 litres/min) at Brumbys-1 where pressure analysis techniques are employed to evaluate the suitability of the reservoir for CO₂ injection. The results indicate that the injection well, Brumbys-3, exhibits suitable injectivity, suggesting its potential for successful CO₂ injection. 

As part of the study, efforts are made to update the previous understanding of the reservoir. By integrating data from the pump test, pressure analysis, and monitoring well, the reservoir model is updated. This model aids in predicting the behaviour of the injected CO₂ and assessing its potential implications. Notably, this project specifically investigates the movement of CO₂ injection along and/or through the fault plane. 

Direct Air Capture has grown in importance as a prospective mitigation technology and an option for providing a renewable and sustainable carbon feedstock. However, there are very large engineering and commercial hurdle to its successful deployment.  I will present an update on its current status and highlight future developments and provide a perspective on its place in the future.

AspiraDAC is an Australian DAC technology provider, that proudly leads the global charge with the world's pioneering solar-powered Direct Air Capture (DAC) system. At its core, AspiraDAC is distinguished by cutting-edge innovations, prominently featuring advanced metal-organic framework (MOF) nanomaterials and a specialized modular DAC design. 

 

The specially designed DAC modular units include an innovative energy solution, to minimise the amount of energy required to capture a specific amount of carbon dioxide.  It is the only DAC solution to integrate the energy supply with the capture technology.  Being modular, its pathway to scale is via large scale manufacture, leveraging the cost reduction strategies of industries such as solar pv and automotive.

 

Noteworthy is AspiraDAC's integration of innovation, renewable energy utilization, and environmental stewardship, offering a holistic approach to the global imperative of carbon reduction in the face of climate change. The presentation will provide summary of AspiraDAC technology and its journey in creating an Australian native DAC technology to solve climate change.  AspiraDAC's strides towards DAC with permanent geological storage of captured CO2 exemplify not only a great example of Australian CCUS solutions but also reinforce Australia's pivotal role in shaping a greener and more sustainable future.  

Direct air capture is now considered an essential part of the portfolio of technologies that can enable us to limit global warming to acceptable levels. Apart from geological storage of the product CO₂, it can also be used for the manufacturing of carbon neutral chemicals. CO₂-capture from air is challenging because the low CO₂ concentration requires huge amounts of air to be moved through the contactors and the thermal release of CO₂ from the capture agents will require significant amounts of energy.

 

Here we provide a technical development roadmap by which liquid-absorbent based CO₂-capture processes, the leading technology in CO₂-capture, can be used for air capture. This is advantageous as one can build upon the existing and standard design and engineering practices, which will facilitate development and deployment. The technical roadmap is based on the following staged approach:

This approach reveals that CO₂-capture costs below $100/t CO₂ are achievable.

The outcome of the technical roadmap is used for an estimate of costs to produce methane from CO₂ and H₂, which results in a renewable fuel that could be exported using the existing infrastructure that can compete with export of liquid hydrogen.

Direct Air Capture (DAC), a groundbreaking concept in the realm of climate solutions, has emerged as a pivotal avenue for achieving negative emissions. By directly extracting CO₂ from ambient air, DAC offers a unique advantage by addressing the root cause of increasing atmospheric CO₂ levels. Among DAC methodologies, the adsorption-desorption process utilizing solid adsorbents presents notable promise. However, the large heat of adsorption requires high energy consumption for regeneration of adsorbents, significantly compromising the economic viability and productivity of DAC. 

Here, we show a vapor promoted DAC process to recover the adsorbed CO₂ by in situ vapor purge using water harvested from atmosphere synergistically. The desorption of CO₂ is substantially enhanced in the presence of concentrated water vapors at around 100 °C, resulting in the concurrent production of 97.7% purity CO₂ and fresh water without the use of vacuum pumps. Moreover, we demonstrate a prototype of this DAC powered by sunlight, which recovers 98% of the adsorbed CO₂, the highest among all other DAC technologies, and consumes 20% less thermal energy. 

In another case when 10 kPa vacuum is applied, this in situ vapor purge can achieve near complete regeneration of the chemisorbents at temperatures as low as 60 °C, producing 99% purity CO₂ with a stable working capacity of 1.10-1.13 mmol/g for 45 cycles. The minimum work required for regeneration was only 1.62 MJ/kgCO₂, over 37% lower than temperature-vacuum swing desorption. This low-temperature regeneration process not only reduces the energy demand but also reduces the overall cost of DAC.

People in this sector tend to talk in acronyms and assume the audience knows what they are talking about. I used three in my very short title. No wonder peoples’ eyes sometimes glaze over when talking about this subject. I hope to provide clarity and insight into this sometimes complex and evolving space.

 

I aim to highlight how Direct Air Capture (DAC) is being supported in the Voluntary Carbon Market (VCM) through Standards and Registries, such as Puro.earth and Puro’s CO2 Removal Certificates (CORCs). 

 

This presentation aims to highlight an overview of global initiatives supporting DAC while providing a vision for the future of the DAC industry in Australia. 

In this talk, I will focus on what we can learn from large-scale sequestration in the USA.  Since 2020, 12 Class II and 5 Class VI wells have been permitted for CO2 sequestration in the USA.  Currently, 13 projects report against their M&V plans annually.  This body of experience gives a good idea of what practical M&V plans entail and shows that monitoring geological storage need not be elaborate or expensive.

Distributed fibre optic sensing is attracting more and more attention in CO₂ geological storage. Temperature sensing (DTS) and acoustic sensing (DAS) have been used for pipeline leak monitoring and CO₂ plume imaging in the subsurface. We propose the distributed optical fibre strain sensing technology for deformation monitoring, aiming to provide early warning of well/caprock integrity in fluid injections.

This talk will introduce the latest field results and the great potential for fault integrity/fault zone leak monitoring in geological CO₂ storage.

In the CO₂ release near a shallow fault zone, significant subsurface changes occur within several weeks, and thus require frequent monitor surveys. Thus, this experiment will be monitored with so-called reverse 4D vertical seismic profiling (VSP) with a sparker source in the well and over 1000 receivers on the surface. This method avoids the need for shooting many shot points in each survey as required in conventional 4D VSP, which would make each monitor survey duration too long.  The sparker source also provides ultra-high spatial resolution required for this small injection.

The reverse VSP will be complemented by a trial of time-lapse surface seismic monitoring using refracted waves, with a mobile source and the same array of surface receivers. The monitoring program for the deep injection includes continuous offset-VSP acquisition with permanently mounted surface orbital vibrators as seismic sources and downhole distributed acoustic sensors (DAS) complemented by vibroseis 4D VSP, a combination that proved its efficacy in the Otway Stage 3 Project. It would be useful to complement this proven technology with trials of new approaches, including real-time and in-depth analysis of induced seismicity, real-time continuous reflection data interpretation using machine learning, estimation of CO₂ saturation from direct 

Near-surface environmental monitoring, targeting groundwater and soil gas, plays an important role in the Monitoring, Measurement and Verification (MMV) program at on-shore deep-well carbon capture and storage (CCS) sites. The purpose of environmental monitoring is not only for regulatory compliance but also to assure the public that injection activities do not impact the near-surface environment. 

At the Otway International Test Centre (OITC), environmental monitoring has been conducted annually since before the first injection in 2008, establishing baseline conditions and obtaining 17-year data for soil gas and 18-year data for groundwater. Since mid-2020, the Deakin University team has collected groundwater samples from up to seven monitoring bores and eleven private bores of the local landholders. 

A variety of parameters were gathered to assess groundwater quality, including major ions, trace elements, and tracers (i.e., SF6 and noble gases). Meanwhile, over 100 soil gas sampling points were installed across an area of approximately 3.8 km2, including dairy paddocks and roadsides. Samples were analysed for concentrations of CO2, N2, O2, CH4, and carbon isotopes in CO2 (δ13CCO2), along with the measurement of tracers in selected samples. Significant natural variabilities have been observed temporally and spatially within both groundwater and soil gas systems. 

A multi-step verification process was employed to identify potential influence on the near-surface environment. The verification process incorporates tracer analysis, along with historical values, baseline values, and analysis methodologies established by researchers between 2008 and 2023. Research objectives were established to optimise monitoring strategies based on a substantial database, focusing on risk-based soil gas monitoring. To date, valuable insights have been gained throughout the work at OITC, providing lessons that are invaluable for developing cost-effective monitoring strategies in future largescale CCS projects.
 

We present recent advances in pressure-based monitoring techniques for tracking migrating CO₂ plumes, with field results from the Otway Stage 3 project. We focus on integrating our measurements with other complimentary methods, such as seismic imaging, to reduce uncertainty and provide risk-based monitoring solutions.

We present updated results for pressure tomography using an uncertainty approach with reduced wells and perform simultaneous multi-vintage inversions to help constrain the solution space. We also discuss a joint seismic inversion scheme, which can reconcile results across monitoring modalities.

Finally, we present our recent findings from earth-tide monitoring, which reveals complex amplitude, diurnal and semi-diurnal phase behaviour in the presence of a nearby CO₂ plume.

The leading technology for CO₂-capture is based on the use of liquid absorbents, across a broad range of quite different applications. Over the last decades, the frontier of capture technology development has gradually shifted towards the lower CO₂-partial pressure levels. Also, the composition of the CO₂-containing source gases has dramatically changed with a more recent shift towards emissions abatement from the hard-to-abate industries and the growing interest in CO₂-capture from air. This means that the liquid absorbent CO₂-separation process development has been one of continuous adaptation to changing circumstances and shifting focus. The context for CO₂-capture will also increasingly involve CO₂-utilisation options in addition to CO₂-storage.

 

The presentation will provide an overview of CSIRO’s work in liquid absorbent CO₂-capture over the last two decades. It will discuss how emerging challenges were addressed and what solutions were developed and also provide some insights into the challenges ahead.

Mitigating climate change necessitates the removal of two trillion tonnes of CO2. This colossal undertaking can only be accomplished through large-scale CO2 utilisation facilities capable of processing over a million tonnes of CO2 annually. Even with such facilities, halting global warming would require approximately 200,000 refineries operating for a century. However, if we can achieve an annual removal of 10 million tonnes or more per facility by 2050, the number of required facilities would be reduced to roughly 20,000. Currently, fewer than 1,000 large bio- and petro-refineries are in operation worldwide. Therefore, beyond 2050, additional technological breakthroughs will be needed to reduce the number of facilities to a few thousand. The CO2 utilisation pathway to 2100 can be divided into three stages: 2030 Target Technologies, 2050 Target Technologies, and 2100 Target Technologies. This presentation aims to inform policymakers, industry professionals, academics, and the general public about the potential uses and limitations of CO2 as a feedstock in relation to these three stages.

One potential solution is the commercial-scale utilisation of CO2 for 100% renewable products and low carbon fuels, which holds significant potential for creating new markets and industries that mitigate climate change. This approach can also support a circular bioeconomy and a future with net-zero emissions. However, there are obstacles to overcome, including technical feasibility, economic viability, environmental impact, and policy and regulatory frameworks. This presentation provides an overview of the technology and potential of CO2 utilisation, as well as the opportunities and challenges for its development and deployment in the immediate to long-term.

We will also discuss currently commercially viable fuels, chemicals, polymers, and construction materials, and propose future technological advancements. This information is intended to stimulate further discussion and action on this topic.

Monitoring and verification of CO₂ plumes is essential in understanding the effectiveness and potential risks associated with Geological Carbon Sequestration (GCS). Despite varying degrees of ambiguity in the regulations for the monitoring requirements in various jurisdictions, all regulators require that the operator monitors the injection, migration, and stabilisation of the plume. Decades of post-injection monitoring can be a costly task that requires careful planning.

The essence of monitoring lies in the regular assessment of the behaviour and movement of the CO₂ plume within the geological storage site. Each risk mechanism component is associated with inherent and operational risks. The assessment of such risks underpins the planned monitoring solution which may include direct or inferred measurements of pressure, temperature, and saturation (or their changes) within the CO₂ storage complex. By monitoring these parameters, the operator can ensure that the stored CO₂ is being contained as intended and is not having an adverse impact (environment, human, reputational) (e.g. significant leakage into the water column).

Verification, on the other hand, focuses on confirming the accurate placement and containment of the CO₂ within the storage complex. This involves the use of various monitoring techniques, such as seismic surveys, well logging, and pressure testing, to assess the integrity of the storage reservoir and detect any potential leaks or migration pathways. Verification is crucial in ensuring the long-term safety and reliability of CCS projects.

Monitoring plans are site-specific, but learnings and best practices can be transferred between projects. This talk aims to introduce some high-level approaches for risk assessment and discuss how this might link to a proposed monitoring plan.

Pilot Energy Limited is an Australian oil and gas producing company transitioning to clean energy. Its flagship Mid West Clean Energy Project aims to develop an integrated CO2 storage service and produce clean ammonia leveraging existing oil and gas infrastructure as well as renewable energy resources.

 

The project is currently in the Pre-FEED/FEED stage. CO2 storage operations are anticipated to commence in 2026 followed by blue ammonia production from 2028. This case study presentation focuses on the CO2 storage aspect of the project. Pilot has encountered numerous technical, regulatory and commercial challenges which has shaped project development. This case study shares Pilot’s learnings to assist the efficient transition of hydrocarbon fields from production to carbon capture and storage (CCS).