Oil and gas producers Santos Limited (ASX:STO) and Repsol, S.A. (BME:REP) are exploring a sale of a minority stake in oilfields in Alaska they jointly own and develop in a deal that could be worth about $1 billion, according to people familiar with the matter. The oilfields include the Pikka project, which is one of the largest oil prospects in Alaska and has been valued at about $4.5 billion by consultancy firm Rystad Energy. The companies are working with an investment bank to jointly sell minority stakes in Pikka, alongside partial interests in the Horseshoe and Quokka fields that are located in the North Slope region of Alaska, the sources said, requesting anonymity as the discussions are confidential.

Repsol and Santos declined to comment. The stakes are so-called non-operating positions, meaning the owner gets a share of the proceeds from the sale of hydrocarbons without needing to undertake any drilling or be involved in operations. They are required to contribute to their share of costs.

Potential buyer interest will likely be impacted by factors including legal and environmental risks, the sources said, cautioning a deal is not guaranteed.