Exxon Mobil has made oil discovery in Liza-1 well on the Stabroek Block, located approximately 120 miles offshore Guyana.
The well, which is the first on 6.6-million acre Stabroek Block, has been drilled to 17,825ft in 5,719ft of water.
Drilled by ExxonMobil affiliate Esso Exploration and Production Guyana on 5March, the well encountered more than 295ft of oil-bearing sandstone reservoirs.
ExxonMobil Exploration president Stephen Greenlee said: "Over the coming months we will work to determine the commercial viability of the discovered resource, as well as evaluate other resource potential on the block."
In the coming months, the company will assess the well data to determine the full resource potential.
Esso Exploration and Production Guyana holds 45% stake in the block while Hess Guyana Exploration and CNOOC Nexen Petroleum Guyana own 30% and 25% interest respectively.
The publicly traded international oil and gas company, ExxonMobil is a refiner and marketer of petroleum products.