Canada’s Antrim Energy has awarded a contract to Offshore Installation Services (OIS) to permanently plug and abandon four subsea wells in the UK Central North Sea.

Under the contract, OIS will the three wells being abandoned will comprise three suspended wells on the Fyne Licence (P077, Block 21/28a) with one well on the Erne Licence (P1875, Block 21/29d).

The contract will be carried out as part of a ten-well abandonment campaign, which also includes six central North Sea wells from Centrica Energy.

According to OIS, an Acteon company, the campaign will include complete offshore and onshore project management, vessel charter, equipment and personnel.

OIS president Rhodri Davies said: "Since 1996, OIS has successfully completed more than 118 well decommissioning projects without a single lost-time incident.

"With Antrim Energy and Centrica Energy now involved in our 2015 subsea well abandonment campaign, OIS is currently decommissioning ten subsea wells within the UK Continental Shelf."

"OIS is currently decommissioning ten subsea wells within the UK Continental Shelf."

OIS will use Acteon sister company, Claxton’s suspended well abandonment tool (SWAT) to decommission the sites in categories 2.1 and 1.

The diverless, vessel-based approach SWAT will be completed as part of a multi-operator campaign in summer 2015, which would be conducted from an anchor-handling tug supply vessel (AHTS), the Island Valiant.

In the initial phase, SWAT will be deployed through the vessel’s moon pool to set cement plugs in the bore and across all the casing annuli.

During the second phase, the wells will be cut and removed from the seabed using an abrasive severance system.

The ten-well abandonment campaign is expected to take about 45 days to complete.

Image: OIS will execute the contract as part of a ten-well abandonment campaign. Photo: courtesy of Offshore Installation Services Ltd.