UK-based energy provider Perenco has successfully injected carbon dioxide into a depleted natural gas reservoir in the southern North Sea.
The injection was carried out by the Project Poseidon joint venture, which includes Perenco, carbon capture specialist Carbon Catalyst, and oil company Harbour Energy.
The CO2 was injected from offshore contractor Petrodec’s ERDA rig – the first such UK rig approved for CO2 injection support – into the Leman 27H platform, part of the Leman gas field.
A total of 5,000 tonnes of CO2 was transported to the offshore site in pressurised containers across 11 separate shipments. Once onsite, the CO2 was transferred to the injection platform, where it was compressed and injected into the reservoir through dedicated wells.
Overview of Project Poseidon ©Perenco
In total, Perenco completed 15 injection cycles, each generating data to inform the next phase of carbon storage development in the region.
Perenco CEO Armel Simondin said the test met the venture’s expectations, both in terms of technical execution and the quality of data gathered.
“These insights are instrumental as we move to the next phase of developing the Poseidon Project,” he added.
How does CO2 injection work?
Each CO2 injection cycle involves a sequence of operations:
• Pressurisation – CO2 is compressed to the required pressure for injection
• Injection – The CO2 is pumped into the target reservoir through a well
• Monitoring – Pressure, flow rate, and other data are tracked in real time
• Shut-in/soaking – The well may be sealed temporarily to observe reservoir response
• Data collection – Sensors log pressure, temperature, and seismic data during each cycle
Safety and monitoring
The long-term safety and reliability of offshore CO2 storage has raised concerns among some environmental groups, particularly regarding the potential for leakage from geological formations. In a recent technical report, the International Energy Agency noted that while the risk of leakage is low, robust safeguards and monitoring are essential.
Perenco said it is addressing these concerns through continuous real-time monitoring, detailed data logging and comprehensive site characterisation to ensure and evaluate the integrity of the storage reservoir.
