GEORGETOWN, Guyana — ExxonMobil has begun drilling a new appraisal well at the Ranger discovery in the Stabroek Block offshore Guyana as part of a wider effort to determine whether two of its major oil finds can support future large-scale developments.
The U.S. oil supermajor is also preparing to spud another appraisal well at the Barreleye discovery, ExxonMobil Guyana President Alistair Routledge announced Monday during a press conference in Georgetown.
“We’ve recently completed the Barreleye-2 well… we ran a drill stem test and that’s given us data that we are now working our way through,” Routledge said. “We anticipate actually coming back to the Barreleye reservoirs and doing further tests — Barreleye-3 — either later this year or going into early next year.”
The Barreleye-1 discovery was made in 2022 and encountered about 230 feet (70 meters) of hydrocarbon-bearing sandstone in 3,840 feet (1,170 meters) of water. ExxonMobil has since conducted a series of appraisal activities to determine the reservoir’s full commercial potential.
Routledge confirmed that the Stena Carron drillship is currently working at Ranger-3, where the company plans to drill, conduct a drill stem test and stimulate the reservoir.
“We’re drilling the Ranger-3 well and then we’re going to run a drill stem test and also stimulate the reservoir to see whether we can economically produce it,” he said.
According to Guyana’s Maritime Administration Department, operations at Ranger-3 began on Sept. 8 and are scheduled to conclude on Dec. 31, 2025.
The Ranger discovery, made in 2018, is one of the most geologically unique finds in the Stabroek Block. Unlike most of ExxonMobil’s sandstone discoveries, Ranger is located in a carbonate reservoir, a formation that can yield very high production rates if successfully stimulated. The initial Ranger-1 well encountered approximately 230 feet (70 meters) of high-quality, oil-bearing carbonate rock.
ExxonMobil and its partners Hess Corp. and CNOOC have discovered more than 30 oil fields in the 6.6-million-acre Stabroek Block, totaling an estimated 11 billion barrels of recoverable resources, according to government and company figures. Production has already started at three floating production vessels, and additional projects are in various stages of planning and approval.
Analysts say successful appraisal at Ranger or Barreleye could anchor future standalone developments or be tied into larger multi-field production hubs. The government has repeatedly emphasized the long-term economic importance of sustained development in the Stabroek Block, which is expected to generate billions of dollars in revenue for Guyana over the next decade.
Routledge said ExxonMobil remains committed to expanding its operations in Guyana as appraisal and reservoir testing continue.
“We’re still in the process of understanding the full potential of these reservoirs,” he said.