Petrochemical giant ExxonMobil has discovered additional oil reserves in an offshore Guyanese field, raising the estimate of its Payara discovery to nearly 500 million oil-equivalent barrels.

The discovery of additional oil was made after successful drilling of the Payara-2 well in the Payara reservoir by its affiliate Esso Exploration and Production Guyana.

ExxonMobil says that the positive well results would increase the Stabroek Block’s estimated gross recoverable resource to 2.25-2.75 billion oil-equivalent barrels.

The drilled well had encountered 59ft of high-quality, oil-bearing sandstone in the Payara field, stated the petrochemical company.

According to ExxonMobil, the Payara-2 well, which is 12mi northwest of the recently funded Liza phase 1 project, was drilled safely to 19,068ft in nearly 7,000ft depth of water.

ExxonMobil Exploration Company president Steve Greenlee said: “Payara-2 confirms the second giant field discovered in Guyana.

“Payara, Liza and the adjacent satellite discoveries at Snoek and Liza Deep will provide the foundation for world class oil developments and deliver substantial benefits to Guyana. We are committed to continue to evaluate the full potential of the Stabroek Block.”

The $4.4bn Liza phase 1 project is also on the 6.6 million acre-Stabroek Block, located about 130mi offshore Guyana. With a stake of 45%, Esso Exploration and Production Guyana is the operator of the block.

Other stakeholders in the Stabroek Block are Hess Guyana Exploration which has a stake of 30% and CNOOC Nexen Petroleum Guyana which holds the remaining stake of 25%.

In January, ExxonMobil along with its partners had discovered oil at the Payara-1 well after the Stena Carron drillship encountered over 95ft of high-quality, oil-bearing sandstone reservoirs.

Image: The Stena Carron drillship at sea. Photo: courtesy of Hess Corporation.