The full story of the US Gulf of Mexico discovery that became Stampede dates back to 2005, when Unocal, ultimately acquired by Chevron, made the Knotty Head discovery in Green Canyon Block 512, writes Kathrine Schmidt.

Hess had an adjacent area, Pony, to the north on blocks 468 and 469, and drilled follow-up appraisal wells.

It became clear that the partners had come upon a major accumulation, which today is believed to contain between 300 million and 350 million barrels of oil equivalent.