Rig mobilizes for ‘UK’s first CO2 well injection’

A 1981-built non-propelled self-elevating cantilever jack-up rig has mobilized for the commencement of what will be the UK’s first CO2 well injection test.

Perenco UK and Carbon Catalyst Limited secured a license to progress the Poseidon CCS project at the Leman gas fields in the UK southern North Sea in August 2023. In November, Wintershall Dea came on board the project by buying a 10% interest from Carbon Catalyst, marking the company’s entry into a second UK CCS project, including the Camelot license.

The partners announced the mobilization of the Petrodec HAEVA offshore workover rig on August 15, which is on location at the Leman Hotel wellhead platform in the UK Southern North Sea.

This marks the beginning of preparatory well operations, setting the stage for the commencement of “the UK’s first CO2 well injection test later this year”, Carbon Catalyst Limited said.

The operation that is expected to take around 30 days includes the workover of the Leman 27H gas production well and the completion of the well into a CO2 injector.

The HAEVA rig was built in 1981 by Hitachi-Zosen in Osaka Works, Japan, and is designed for operations in up to 65 meters of water depth with a drilling depth of approximately 30,000 feet. The unit was originally designed as a drilling rig, mobile offshore drilling unit (MODU), before being converted to a mobile offshore decommissioning unit.

Leman is said to be the largest reservoir complex in the UK Continental Shelf (UKCS), offering a mixture of depleted gas reservoirs and saline aquifers in which to permanently store recovered CO2. The ultimate storage capacity is around 1,000 Mt. The field is connected to the PUK Bacton Terminal, which will receive and process CO2 offshore.

The project is due to come online by 2029. Initial CO2 injection rates will be circa 1.5 million tonnes per annum (Mtpa), ramping up to ~10 Mtpa by 2034, and with further geological potential to peak up to ~40 Mtpa, over a 40-year period.