Production at the $12.7 billion Whiptail project in the 6.6-million-acre Stabroek block, owned and operated by a consortium including Exxon, Hess Corp (HES.N), opens new tab and China's CNOOC Ltd (0883.HK), opens new tab, is expected to begin in 2027.
The project will add capacity of 250,000 barrels of oil per day (bpd), bringing the total gross production capacity of the block to about 1.3 million bpd by end of 2027.
Shares of Exxon were up over 1.2% in morning trade.
Hess estimates a resource base of more than 850 million barrels of oil at the new project.
Exxon in March filed for arbitration over Chevron's (CVX.N), opens new tab plans to buy Hess's Guyana oilfield stake, saying it has the right of first refusal for Hess's stake.
The dispute threatens to derail Chevron's $53 billion takeover of Hess, which has a 30% stake in Stabroek.
