In early 2024, SLB completed a fully integrated CO₂ injection test for the Mitsui E&P Australia (MEPAU) Cygnus Hub Project for Carbon Capture and Storage (CCS). The SLB team deployed the Olga™ dynamic multiphase flow simulator and Symmetry™ process simulation software for CO₂ modeling. Through the fusion of expertise and the application of these cutting-edge modeling technologies, SLB precisely engineered a bespoke solution to meet the project's distinctive demands and injected 100% of the available pressurized CO₂.

Western Australia faces significant challenges with minimizing industrial greenhouse gas (GHG) emissions as its economy is based on hard-to-abate industries including natural resources, agriculture, and manufacturing. Given Australia's national target to cut greenhouse gases by at least 43% by 2030 and achieve net zero by 2050, MEPAU and its partners are advocating for an innovative approach to combating industrial GHGs in Australia: storing CO₂ in depleted gas fields to help reduce emissions by providing a robust, long-term storage solution. Through the Cygnus CCS Hub, MEPAU will support Western Australian industries in decarbonizing their operations and implementing net-zero strategies.

The project encountered a number of challenges, including stringent timelines, complex technical specifications, and regulatory ambiguities surrounding carbon capture legislation. However, working together with MEPAU, SLB leveraged its expertise in oilfield operations, process engineering, CCS legislation, and CO₂ industrial applications to overcome the following challenges:

• Managing the behavior of CO₂: This heat-trapping gas is injectable only under certain reservoir conditions.
• Novel equipment utilization: The team applied novel solutions, including using advanced CO₂ modeling to design a system that reliably pumped and converted liquid CO₂ into vapor. Extensive modeling was crucial to managing risks associated with phase behavior and well integrity.
• Collaboration and knowledge sharing: MEPAU and SLB teams collaborated to share global knowledge on CO₂ pumping to identify cost-effective equipment combinations and solutions.
• Custom development: Custom HSE methodologies and control philosophies were developed for the project, focusing on safety and risk mitigation associated with handling liquid CO₂.
• Regulatory compliance and safety: The SLB team needed to fill gaps in existing standards related to hazardous area zoning for CO₂ to understand and quantify potential CO₂ releases and their impact on HSE. For this, advanced modeling tools were required.

Advanced CO₂ modeling

The SLB team recommended two advanced CO₂ modeling technologies. The Olga dynamic multiphase flow simulator and Symmetry process simulation software meticulously simulated the entire injection process, spanning from the tank to the reservoir.

Through this approach, the simulation allows the team to identify potential issues or challenges that may arise during the CO₂ injection process. This includes understanding how CO₂ behaves under different pressure and temperature conditions and predicting any phase transitions that may occur. Thus, the team can develop strategies to mitigate the associated risks, design equipment and processes for reliably handling CO₂, and ensure that it remains in the desired phase throughout the injection process.

The simulation also enables optimization of the system design and operation. By running multiple scenarios and analyzing the results, parameters can be fine-tuned, such as flow rates, temperatures, and equipment configurations to maximize efficiency and reliability.

The simulation helps ensure regulatory compliance by providing a detailed understanding of how CO₂ behaves within the system and its potential impact on safety and the environment. This information can be used to develop HSE protocols and ensure that the project meets all necessary regulatory requirements.

Overall, simulating the scenario with the Olga simulator and Symmetry software empowered the SLB and MEPAU teams to make informed decisions, mitigate risks, and optimize the design and operation of the CO₂ injection system, ultimately contributing to the success of the project.

An integrated approach

To address both technical and regulatory challenges, collaboration between MEPAU and across SLB domains was crucial—from digital solutions, well construction, reservoir characterization, well testing, production, well integrity, and flow assurance to process engineering and operations. Additionally, SLB and MEPAU engaged with regulators to ensure regulatory compliance, especially in the absence of CCS legislation.

Successful CCS project

Despite facing significant challenges, SLB successfully executed the project by injecting 100% of the available liquid CO₂ into the reservoir via an existing well for proof of concept. This indicates the effectiveness of the solution, and the achievement suggests that the system’s design and operation were optimized to maximize injection rates while mitigating safety and integrity concerns.

To manage the behavior of CO₂, SLB engineered a system to reliably pump and convert liquid CO₂ into vapor before injection, preventing uncontrolled phase transitions and ensuring stable flows. During execution, 45 metric tons of CO₂ was injected into the formation (with a maximum of 54 metric tons allowed by the government), however, the temporary facility was capable of injecting much more volume if available.

The total CO₂ injection of 45 metric tons reveals the scalable offsetting potential of CCS projects, and the operation still managed to be carbon-negative even with such a small scope because of the efficient workflows. The system results are scalable with greater offsetting potential as the scope of the operation increases, which underscores not only the environmental advantages of MEPAU's Cygnus CCS Hub but also its capacity to bolster sustainability in the manufacturing sector in Western Australia and internationally.