Following last week’s edition, we will continue reports of recent oil and gas discoveries in offshore basins internationally. Indeed, there was an encouraging track record during the first quarter of 2026.
Rasoul Sorkhabi
Editor, Core Elements
Offshore Discovery Hotspots in the Americas
Frode Koppang/Shutterstock.com
Gulf of Mexico/America
In April, Occidental announced the discovery of the Bandit prospect in the Gulf of Mexico (America).
The discovery well is located about 125 miles south of the Louisiana coast in Green Canyon Block 680 to a total water depth of 36,535 feet.
The well encountered light crude in Miocene sandstone formations.
Bandit is operated by Occidental, which holds a 45.38 percent interest, and its partners, Chevron (37.13 percent) and Woodside Energy (17.5 percent).
The consortium is evaluating results to determine development options.
The discovery well Copoazú-1 was spudded in November 2025 and drilled about 36 kilometers from the coastline in Block GUA-OFF-0, at a water depth of 964 meters.
The Noble Discoverer semi-submersible rig, which Petrobras hired in December 2023 for its deepwater exploration, drilled the well.
Petrobras is the operator with 44.44 percent interest, in partnership with Ecopetrol (55.56 percent).
The Copoazú-1 well is located eight kilometers from the Sirius-1 field, which Petrobras and Ecopetrol discovered in 2002.
Offshore Brazil
Two recent pre-salt deepwater discoveries in the Campos Basin offshore Brazil highlight the importance of pre-salt plays in the circum-Atlantic margin.
Pre-salt reservoir background:
Seventy-eight percent of oil and gas production in Brazil comes from reservoirs beneath thick salt layers.
These Aptian-age carbonate reservoirs were deposited between 126 and 120 Ma, just below the salt layer deposited at 119 Ma.
A paper by Alkmim and colleagues in Marine and Petroleum Geology details the stratigraphy.
The discovery well 3-BRSA-1397-RJS was drilled 113 kilometers offshore from Campos dos Goytacazes in Rio de Janeiro at a water depth of 1,178 meters.
It is located within the Marlim Sul field, which was discovered by Petrobras in 1987 via well 4-RJS-382.
Discovery well 1-BRSA-1404DC-RJS:
A month after well 3-BRSA-1397-RJS,Petrobras announced this discovery.
The discovery well 1-BRSA-1404DC-RJS is located 201 kilometers off the coast of the state of Rio de Janeiro, at a water depth of 2,984 meters.
Petrobras is the operator of block C-M-477 (70 percent interest), in partnership with BP (30 percent interest).
Why it matters:
Since 2006, Brazil has become a net exporter of oil, thanks to its pre-salt oil fields. Petrobras needs to find new reserves to maintain this status.
Meanwhile, Brazil has insufficient refining capacity and is currently dependent upon international markets for refined products.
Go deeper: For more on the American Equatorial Atlantic margin, read my article inAAPG’s Explorer on the Guyana basin.
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Eastern Mediterranean basins have witnessed a surge in petroleum exploration and major discoveries, driven by international operators and government-backed campaigns.
Shell’s Sirius-1X well, offshore Egypt:
Announced in March, this exploratory well has shown encouraging initial gas indications.
The field is planned to come onstream by 2029.
The Stena IceMAX drillship drilled the well to the target depth of 2,115 meters.
The Sirius reservoir play is in the North East El-Amriya block in the Nile Deltaic Basin.
Operator Shell (60 percent) is partnered with Kuwait Foreign Petroleum Exploration Company (40 percent).
The discovery well Denise W-1 lies about 70 kilometers offshore Port Said in 95 meters of water depth in the Temsah Concession.
The reservoir is sandstone with approximately 50 meters of net pay, similar to the nearby Middle Pliocene Temsah field, which has been in production since 2000.
Preliminary estimates indicate about 2 trillion cubic feet of in-place gas and 130 million barrels of condensate.
Eni holds a 50 percent share in the Denise Development Lease, with BP holding the remaining 50 percent.
Eni’s B2-16/4 and C1-16/4 wells, offshore Libya:
Eni also made two gas discoveries in March—Bahr Essalam South 2 (BESS 2) and Bahr Essalam South 3 (BESS 3)—via discovery wells B2-16/4 and C1-16/4, respectively.
The wells are located about 85 kilometers off the coast at a water depth of 650 feet.
The reservoir is within the Metlaoui nummulitic limestone of Lower Eocene age.
Preliminary estimates put the in-place reserves for both fields at one trillion cubic feet of gas.
Why it matters: These discoveries are politically and financially significant for Libya as the country is coming out of a civil war.
Geliga-1 well is located about 70 kilometers off the coast of East Kalimantan.
The well was drilled at a water depth of 2,000 meters to a total depth of 5,100 meters.
The pay zones are of Miocene age.
The in-place reserves in the field are estimated to be 5 trillion cubic feet of gas and 300 million barrels of condensate.
Drill stem test recorded reservoir flow rates of up to 60 million standard cubic feet per day.
The new discovery is adjacent to the undeveloped Gula gas discovery, estimated to contain 2 trillion cubic feet of in-place gas and 75 million barrels of oil.
The combined Geliga and Gula fields could produce about 1 billion standard cubic feet per day and 80,000 barrels of oil per day.
The Geliga-1 field is in the Ganal exploration block, shared by operator Eni (82 percent interest) and shareholder Sinopec (18 percent).
Why it matters: The new discovery will stimulate international interest in renewed exploration in Southeast Asia.
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