Statoil is in for a fight with Diamond Offshore Drilling after it ditched a rig contract nine months ahead of schedule.
The Norwegian state-controlled oil giant informed the Houston-based contractor that it is quashing its contract for the semi-submersible Ocean Vanguard ahead of time.
Diamond's fleet status report shows that Statoil took the rig in early July 2013 at $454,000 a day and was due to hold onto it until late February next year.
There was also a 20-month option for Statoil to extend the contract.
In a brief statement on Wednesday, Diamond said that it "disputes Statoil's basis for terminating the contract and intends to defend its rights under the drilling contract".
No mention was made of the reasons behind Statoil's decision to axe the deal.
Nobody was immediately available for comment at either the Norwegian oil company or Diamond on Wednesday afternoon.
Intriguingly the Diamond unit was originally intended to carry out a two-well programme for Statoil in the Arctic waters of the Barents Sea, including the Apollo wildcatin the Hoop area. The probe on that prospect, which attracted unwanted attention from Greenpeace, just spudded this week.
Statoil replaced the Ocean Vanguard on that job with the semisub Transocean Spitsbergen. At the time a Statoil spokesperson explained the switch as "part of the normal optimisation of our rig portfolio".
In early May the semisub drilled the 16/2-19A sidetrack on the northern flank of the giant Johan Sverdrup discovery off Norway. The probe was drilled as a follow-up to an earlier positive appraisal of the Geitungen find in Statoil-operated production licence 265.
Licence partner Det Norske Oljeselskap said at the time that the well, drilled to the south-west to test the northern extent of the reservoir, struck a gross 12-metre oil-bearing interval of “medium good reservoir development” in the targeted Draupne formation.
The previous appraisal, 16/2-19, had uncovered six metres of oil-bearing sandstone believed to be part of the Statfjord formation.