Ineos said it has acquired an additional 25% stake of the Clipper gas field in the Scottish North Sea, confirming earlier speculation. The buy raises its stake to 75%, with the remaining 25% continuing to be held by Germany’s Bayerngas.

The field 300 miles northeast of Aberdeen, Scotland originally belonged to Shell. The stake just sold is owned by British gas exploration company Fairfield Energy, which held it in conjunction with 50% partner and operator DEA UK.

Clipper is one of 12 gas fields Ineos bought into earlier this month after DEA, for political reasons, was forced by the British government to divest. DEA was taken over by Russian tycoon Mikhail Fridman’s Letter One investment fund in 2015, at the height of the EU’s dispute with Russia over Ukraine.

As the transaction with Fairfield is not subject to regulatory clearance, Ineos said it was completed on Oct. 28. The earlier transaction with Letter One is currently being reviewed by EU competition authorities as well as the UK regulatory body. The latter is thought certain to give the green light.

Rob Nevin, chairman of Ineos Upstream – the company set up by the Swiss-based petrochemicals giant to own and operate its upstream gas business – called the latest deal “another step forward as we continue to pursue opportunities in the North Sea.”

David Peattie, CEO of Fairfield Energy, said the sale is part of his company’s strategy to become a decommissioning-focused company.”