ExxonMobil returns to little-explored play with new Guyana appraisal well

US company drilling third well in the Ranger area in search of carbonate reservoirs

ExxonMobil chief executive Darren Woods.
ExxonMobil chief executive Darren Woods.Photo: ANDREW MANGUM

US supermajor ExxonMobil has started drilling a new well to appraise the Ranger discovery in the Stabroek block offshore Guyana, targeting additional volumes in an area featuring high potential for carbonate reservoirs.

The well, the sixth discovery made in Stabroek, still holds to date the title of deepest probe ever drilled by ExxonMobil in the block, with the campaign taking place in 2735 metres of water to a final depth of 6450 metres.

Ranger-1 is a carbonate play and located in an area with different geology than other discoveries made in sandstone reservoirs in Guyana.

One appraisal well, Ranger-2, was drilled in 2019 and now, six years later, ExxonMobil has returned to the area to spud the Ranger-3 appraisal well.

According to updated information provided by Guyana’s Maritime Administration Department (MARAD), ExxonMobil initiated this week drilling of the Ranger-3 prospect with the Stena Drilling drillship Stena Carron.

Ranger-3 is being drilled some 253 kilometres from the Guyanese coast and closer to the border that separates Stabroek from the Kaieteur block to the north, where ExxonMobil in November 2020 failed to detect commercial quantities of hydrocarbons with the Tanager-1 exploration well.

The Ranger-3 programme is due for completion later this year. Exploration for carbonates are like those for sandstones, but new tools, techniques and interpretation methodologies are required to address specific challenges to drill and produce from these reservoirs optimally.

In the past, ExxonMobil classified Ranger as a small find, noting it would not be economically viable as a standalone development.

The new appraisal well could change this perspective depending on the results. Analysts have previously estimated Ranger to hold between 500 million and 600 million barrels of oil.

ExxonMobil is already producing more than 700,000 barrels per day of oil in the Stabroek block from four floating production, storage and offloading vessels in the Liza, Payara and Yellowtail fields.

The company has made over 30 discoveries in Stabroek since 2015 and has so far unlocked more than 11 billion barrels of oil equivalent in recoverable resources in Guyana.

ExxonMobil operates Stabroek with a 45% stake and is partnered by US peer Chevron on 30% and China’s CNOOC International on 25%.

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Published 8 September 2025, 13:02Updated 8 September 2025, 13:02
GuyanaExxonMobilStabroek BlockStena DrillingAmericas