Norway’s Equinor has put on hold the drilling of a key exploration well in the Barents Sea after a well incident last week, the company said on Jan. 21.

The incident occurred when Seadrill’s rig West Hercules was drilling the Gjoekaasen well offshore Norway.

The so-called “high-risk, high-impact” well could hold between 26 million and 1.4 billion barrels of oil equivalents, one of Equinor’s partners, Aker BP, said last week.

Other partners include Sweden’s Lundin Petroleum and Norwegian state-owned oil company Petoro.

During the incident the lower mariner riser package on the blowout preventer was unintentionally disconnected for still unknown reasons.

No personal injuries or harm to the environment occurred during the incident, in which a device used to protect a subsea well and prevent blowouts was disconnected, the Norwegian Petroleum Safety Authority (PSA) said in a statement.

“Operations are stopped until we know the cause of the disconnect. Rig owner Seadrill has initiated an investigation into the incident, where Equinor participates,” a spokesman for the oil company said in a statement to Reuters.

Seadrill was not immediately available to comment.

The PSA said it would investigate the incident.

Offshore