Exxon Mobil has made an oil discovery from Liza-2, the second exploration well in the Stabroek block in offshore Guyana.
The discovery has a recoverable resource ranging between 800 million and 1.4 billion oil-equivalent barrels.
Liza wells are located in the Stabroek block 193km offshore from Guyana.
The company is currently evaluating data from the successful Liza-2 well test.
Exxon Mobil Exploration president Steve Greenlee said: "We are excited by the results of a production test of the Liza-2 well, which confirms the presence of high-quality oil from the same high-porosity sandstone reservoirs that we saw in the Liza-1 well, completed in 2015.
"We, along with our co-venturers, look forward to continuing a strong partnership with the government of Guyana to further evaluate the commercial potential for this exciting prospect."
ExxonMobil’s affiliate Esso Exploration and Production Guyana drilled the Liza-2 well 3.3km from the Liza-1 well.
The well was drilled to 17,963ft in 5,551ft of water and encountered more than 190ft of oil-bearing sandstone reservoirs in upper Cretaceous formations.
Greenlee added: "This exploration success demonstrates the strength of our long-term investment approach, as well as our technology leadership in ultra, deepwater environments."
The 26,800km² Stabroek block is operated by Esso Exploration and Production Guyana, which holds a 45% interest in it. Hess Guyana owns 30% and CNOOC holds 25% interest.