BP (NYSE: BP) and Kosmos Energy (NYSE: KOS) have won exploration rights to two offshore oil blocks in Sao Tome and Principe’s exclusive economic zone, the national oil agency said on Jan. 23.

The two companies won Blocks 10 and 13 in a restricted tender, the agency’s director Orlando Pontes said in a statement on Jan. 22. They beat a second consortium of Portugal’s Galp Energia and Total (NYSE: TOT), he said.

Sao Tome and Principe, a tiny island nation in Africa’s Gulf of Guinea, is surrounded by oil-rich neighbors Nigeria, Cameroon, Equatorial Guinea and Angola.

Despite a lack of significant discoveries after several years of prospecting, the industry sees its waters as likely to yield oil eventually, and several firms are currently exploring.

Its 49807-sq mile (129,000-sq km) exclusive economic zone is divided into 19 blocks.

New York-listed Kosmos Energy, which is active in other parts of West and Central Africa, acquired licenses to Blocks 5, 6, 11 and 12 in 2015 and 2016. The national oil agency said it expected the firm to begin drilling in 2019 based on seismic results.