Fortune | Spanish Oil Repsol Company Makes Biggest US Onshore Find in 30 Years Fortune The Madrid-based energy company had partnered with Armstrong Oil and Gas to unearth the source of oil located in Alaska's North Slope, which borders the Arctic Ocean. The two firms have been working together to explore Alaska's oil potential since 2011. Massive oil discovery in Alaska is biggest onshore find in 30 years Companies claim largest US onshore oil discovery in 30 years Largest US onshore oil discovery in 30 years announced: 1.2B barrels in Alaska |