Phillips Petroleum Company was an American oil company incorporated in 1917 that expanded into petroleum refining, marketing and transportation, natural gas gathering and the chemicals sectors. It was Phillips Petroleum that first found oil in the North Sea on December 23, 1969, at a position that was later named Ekofisk.

Ekofisk is an oil field in block 2/4 of the Norwegian sector of the North Sea about 320 km (200 mi) southwest of Stavanger. Discovered in 1969 by Phillips Petroleum Company, it remains one of the most important oil fields in the North Sea. This was the first discovery of oil after the drilling of over 200 exploration wells in the North Sea "triggered" by the Groningen gas field discovery. In 1971, Phillips started producing directly to tankers from four subsea wells. Oil production is planned to continue until at least 2050.