U.S. oil major ExxonMobil said Wednesday it had made another oil discovery in the Stabroek block offshore Guyana, this time at the Longtail-3 well.
"Drilling at Longtail-3 encountered 230 feet (70 meters) of net pay, including newly identified, high-quality hydrocarbon-bearing reservoirs below the original Longtail-1 discovery intervals. The well is located approximately two miles (3.5 kilometers) south of the Longtail-1 well," ExxonMobil said.
The Longtail-1 discovery in the Stabroek Block was drilled in 2018, encountering approximately 256 feet (78 meters) of high-quality, oil-bearing sandstone reservoir.
The Longtail-3 well was drilled in more than 6,100 feet (1860 meters) of water by Stena Drilling's Stena DrillMAX drillship.
"Longtail-3, combined with our recent discovery at Uaru-2, has the potential to increase our resource estimate within the Stabroek block, demonstrating further growth of this world-class resource and our high-potential development opportunities offshore Guyana,” said Mike Cousins, senior vice president of exploration and new ventures at ExxonMobil.
Cousins did not say by how much the resource estimate would be increased. To remind, when announcing Uaru-2 discovery in April, ExxonMobil said Uaru-2 would add to 9 billion oil-equivalent barrels discovered in the block in recent years.
ExxonMobil has deployed two additional drillships in the first quarter of 2021; the Stena DrillMAX and the Noble Sam Croft to enable further exploration and evaluation while continuing development drilling activities offshore Guyana. As the company advances its 15-well campaign in the Stabroek block, the Stena DrillMAX drillship will move to the Whiptail-1 well, while the Noble Sam Croft supports development drilling for Liza Phase 2.
In other drilling activity in the Stabroek Block, the Mako-2 evaluation well confirmed the quality, thickness and areal extent of the reservoir, ExxonMobil said.
"When integrated with the previously announced discovery at Uaru-2, the data support a potential fifth floating production storage and offloading vessel in the area east of the Liza complex. The Koebi-1 exploration well in the Stabroek block has shown evidence of non-commercial hydrocarbons," ExxonMobil added.
ExxonMobil affiliate Esso Exploration and Production Guyana Limited is the operator and holds 45 percent interest in the Stabroek Block. Hess Guyana Exploration Ltd. holds 30 percent interest and CNOOC Petroleum Guyana Limited, a subsidiary of CNOOC, holds 25 percent interest.
Hess CEO John Hess said: “The Longtail-3 discovery together with the previously announced discovery at Uaru-2 will add to the gross discovered recoverable resource estimate of approximately 9 billion barrels of oil equivalent and underpin future development opportunities for the Stabroek Block."
The Stabroek Block is 6.6 million acres (26,800 square kilometers) large.