Decarbonisation Technology - November 2024 Issue

The tracers accurately assessed the flow behaviour and sweep efficiency of the injected CO₂. Without them, it would have been difficult to differentiate between the injected CO₂ and the naturally occurring CO₂ in the reservoir, complicating the determination of physical movement between injectors and producers. The most significant findings include: ○ Detection of physical communication: Tracers confirmed physical communication between the CO₂ injection well (K12-B6) and the nearest producer well (K12-B1). Tracers were detected in the gas stream of K12-B1 approximately four months after the start of CO₂ injection, validating the expected migration paths and reservoir connectivity. ○ Understanding reservoir dynamics: Tracers facilitated a better understanding of reservoir behaviour and pressure dynamics. The data obtained helped interpret complex down-hole pressure data, which is crucial for optimising storage and recovery processes. ○ Early detection of issues: The precision of tracer technology enabled the early detection of potential issues, such as unexpected pressure disturbances. This early warning capability is essential for proactive management and mitigation of any risks associated with CO₂ storage. transformative impact of tracer technology on CO₂ storage and monitoring. By providing accurate tracking of CO₂ migration and verifying the integrity of storage sites, tracer technology offers a robust solution to the challenges of CCS. The successful application of tracer technology at the K12-B site underscores its potential to enhance our understanding of CO₂ storage and Conclusion The K12-B case study highlights the recovery processes. The ability to track CO₂ movement with high precision and detect leaks or migration issues early contributes significantly to the overall safety and effectiveness of CCUS initiatives. Harnessing experience from the In Salah CO₂ storage project The In Salah CCS project in central Algeria is a pioneering example of onshore CO₂ capture and storage. With a history of more than two

decades, this project has amassed a wealth of relevant knowledge for CC initiatives worldwide. Background This project captures CO2 from multiple gas fields at a central processing facility. The captured CO2 is then compressed, transported, and injected into a 1.9km deep carboniferous sandstone formation at the Krechba field. Since its inception in 2004, the project has successfully stored more than 3.8 million tons of CO₂. Challenge The In Salah project involved an aquifer with limited prior knowledge. A unique aspect of this project was the effort to reduce costs associated with CO₂ storage and to cut the costs by using CO₂ from their own operations. Abated CO₂ from the Krechba field helped to address the issue of high CO₂ content in their natural gas, which affected its marketability. The primary risk for the project was regulatory scrutiny and stakeholder concerns. Authorities needed assurance that “ Developing a comprehensive and cost-effective monitoring strategy was essential to verify that the CO 2 remained securely stored ” the CO₂ was being properly monitored and not being reintroduced into the production stream, which could be seen as fraudulent. Ensuring that CO₂ was not re-emerging was critical to avoid potential penalties. Developing a comprehensive and cost-effective monitoring strategy was essential to verify that the CO 2 remained securely stored. This required a diverse portfolio of monitoring technologies to track the behaviour of the CO2 and detect any potential leaks. Additionally, the project faced geological and geo-mechanical complexity. The storage reservoir consisted of low permeability and fractured sandstone, making it crucial to understand the intricate geological characteristics and the behaviour of CO2 within this complex environment. Solutions To ensure effective monitoring, a broad array of geophysical and geochemical techniques