Repsol and its partner Armstrong Energy announced that they have made the largest onshore conventional hydrocarbon discovery in the US in 30 years. The Horseshoe-1 and -1A wells, drilled the winter of 2016–2017, confirm the Nanushuk play as a significant emerging play in Alaska’s North Slope, Repsol said. Contingent resources in the two companies’ Nanushuk blocks, identified from existing data, could amount to 1.2 billion bbl of recoverable light oil, Repsol said. The company holds a 25% interest in the Horseshoe discovery and a 49% interest in the Pikka Unit, which would be the play’s first producing field if developed. Armstrong, the discovery and unit operator, holds the remaining interests in both.