Repsol Chairman Antonio Brufau said in a statement that the deal with Colorado energy companies 70 & 148 LLC and GMT Exploration LLC are a "perfect fit" for his company's effort to balance its portfolio with low risk assets.
"We are confident that our worldwide experience combined with a partner with an extensive local knowledge is going to deliver value in the near future," he added.
Both Colorado companies have been involved in Alaska for around 10 years and are the largest lease holders in the state.
The blocks involved in the deal cover more than 750 square miles in the North Slope of Alaska. Exploratory work is scheduled for late 2011.
The U.S. Geological Survey in October determined that there are around 896 million barrels of undiscovered oil in the National Petroleum Reserve in Alaska, about 90 percent less than 2002 estimates.
The NPRA is federal land that lies west of the Arctic National Wildlife Refuge in the North Slope of Alaska.