Could Jethro become Guyana’s next standalone oil development? The Orinduik Block discovery has been viewed that way since August 2019, when Tullow Oil said the find could hold more than 100 million barrels of recoverable oil and support a development offshore Guyana.
Tullow announced the Jethro-1 discovery after the well encountered 55 meters of net oil pay in lower tertiary sandstone reservoirs. The company said the prospect had “commercial and fiscal terms” and pointed to an appraisal program in 2020 to test its viability as a standalone development.
“The results at Jethro-1 exceed our expectations with more than 100 million barrels of oil in a prospect with commercial and fiscal terms,” Tullow’s Chief Executive Officer [CEO] Paul McDade said in August 2019. He also said the company was “confident of the commercial value” of the prospect as a standalone development.
The Orinduik Block lies about 170 kilometers offshore in the Guyana-Suriname Basin and covers 1,800 square kilometers. At the time of the discovery, Tullow held a 60% operating stake, while TotalEnergies held 25% and Eco (Atlantic) held 15%.
‘Heavy oil’ at Orinduik Block could be developed with floating production facility – Eco | OilNOW
Eco Atlantic, currently the sole block holder, kept that development case alive in August 2022, when it said the partners were revisiting the commercial potential of Jethro because of sustained oil prices and had brought in a third-party consultant with heavy-oil development expertise to assess possible drilling and production scenarios.
The company said the discovery’s characteristics appeared favorable for a floating production facility. Eco said Jethro-1 had “the advantage of 8,500 PSI reservoir,” a high reservoir temperature of 94 degrees Celsius, and an estimated flowing wellhead temperature of 90 degrees, factors it said would improve oil mobility and support production.
That view sharpened again in October 2025. Eco Chief Executive Officer Gil Holzman said ExxonMobil’s Hammerhead sanction changed how the company looked at Jethro and the wider tertiary play in Guyana.
“All of a sudden, they came up with Hammerhead and actually proved that they can develop and make economic, a heavy oil discovery…” Holzman said in October 2025. He said that pushed Eco “to take a fresh look into the Jethro one-billion-barrel oil discovery that we had in 2019…to potentially re-evaluate and recall the non-commercialization notice.”
Holzman also said the company hoped to secure “the revaluation right of the Jethro discovery” as it reconsidered farm-out and license options on the block. As of 2026, that October 2025 update remains the latest public indication that Jethro is still being considered as a possible standalone development offshore Guyana.
