It was not immediately clear if the strike would impact the field’s oil and gas production. Ekofisk produced some 72,300 boe/d in November 2023 (the latest data available), according to the Norwegian Offshore Directorate.
The planned action is a protest against the use of non-union labor by another oil services group, SLB UK, which is conducting work at Ekofisk, the IE&FLT union said.
Some 52 of the workers are employed by oil service group Archer, while 23 are employed by ConocoPhillips, the union said in a statement.
The union was also prepared to escalate the strike, it added.
Conoco’s partners at Ekofisk include TotalEnergies, Var Energi, Sval Energi and Norwegian state-owned firm Petoro.
Conoco said it was continuing its dialogue with SLB to “find a solution” and said it was not a party in the conflict between SLB and the union.