U.S. oil company Marathon Oil announced Monday it encountered a natural gas layer measuring more than 150 feet thick while drilling off the coast of Gabon. French energy company Total, the operator of the site, said it spent $922 million on developments in Gabon, a 20 percent increase from 2012.
The discovery in Gabon was located in a pre-salt basin, a sub-sea deposit located under a thick layer of salt. Investors said they expected West African deposits to mirror oil development from off Brazil.
"Instead, they got gas, and not so much of it either," Oppenheimer & Co. analyst Fadel Gheit was quoted as saying by the Houston Chronicle's energy blog Fuel Fix.
Petroleo Brasileiro, known also as Petrobras, said at a Houston energy conference in May it expected to produce more than 2 million barrels of oil per day by 2020 from pre-salt basins offshore, Fuel Fix said.
An estimated 50 billion barrels of oil lie off Brazil's coast, a volume that's expected to put the Latin American country on par with some of the world's top oil producers.
Notable deaths of 2014 [PHOTOS]