Agreement for ExxonMobil Participation with a 60% Stake in the Energean – Helleniq Energy Consortium holding hydrocarbon exploration rights in “Block 2” in the Ionian Sea, with the next step being implementation -for the first time in 40 years- exploration drilling was signed today within the framework of the Intergovernmental Transatlantic Energy Cooperation (P-TEC).
It is noted that the last time an exploratory drilling was conducted in Greek waters to discover a new deposit was with the Nireas-1 and Olympia-1 drillings off the Thermaic Gulf in 1986.

The agreement was signed in the presence of U.S. Energy Secretary Chris Wright, Interior Secretary (and head of the National Energy Sovereignty Council) Doug Bergam, Environment – Energy Secretary Stavros Papastavrou, and the U.S. Ambassador to Athens Kimberly Guilfoyle.
The agreement was signed by John Ardill, Vice President for Global Exploration at ExxonMobil, Andreas Siamisis, CEO of Helleniq Energy, and Mathios Rigas, CEO of the Energean Group.
“We have exploration activities in the Eastern Mediterranean, and we are expanding them into Greece,” Mr. Ardill emphasized in his speech, also highlighting the importance of utilizing domestic energy sources to reduce costs, ensure supply security, support artificial intelligence, and foster development.
Mr. Rigas stated that he is proud of the participation of the American multinational in “Block 2,” where, as he noted, “we have been working since 2020, and it has the potential to make Greece independent. With U.S. support, we will conduct the first drilling in 40 years; it is time for Greece to find its own natural gas supply sources.” He set the drilling timeframe for 2026–2027.
Mr. Siamisis stressed that “Block 2” is the most mature and is moving to the next phase of exploration. He also described it as a significant step both for the Consortium and for Greece and Europe as a whole.
Block 2
Block 2 is the most mature concession for conducting exploratory drilling to determine the presence of commercially viable hydrocarbon deposits, with an estimated success probability of 15–18% (High Risk – High Reward). Formally, the commitment to carry out an exploratory drilling should be made by March 2026 to officially submit the request for transition to the next (second) exploration period to the Hellenic Hydrocarbon Resources Management (EDEYEP). If the required licensing procedures proceed smoothly, the drilling could take place within the next two years.
The Asopos-1 exploratory well will examine a potential carbonate reservoir at a depth of 4,000 meters, targeting a possible deposit of approximately 200 billion cubic meters (bcm) of natural gas.
The agreement provides for ExxonMobil to acquire 60% of the concession. According to the agreement, the Consortium’s shares are as follows:
- ExxonMobil 60%
- Energean Hellas 30%
- HelleniQ Upstream Western Corfu 10%
Energean remains the Operator during the exploration period, while in the event of a hydrocarbon discovery, ExxonMobil will take over operations for development.
In 2022, 2,244 sq. km of 3D seismic data were acquired, the processing and interpretation of which confirmed the “Asopos” structure as the most mature target for exploratory drilling. The initial estimate of possible resources (Gas Initially In Place) is approximately 7.0 trillion cubic feet (tcf) or about 200 bcm of natural gas.
The goal is to confirm a new geological play in one of the largest mapped structures in the Mediterranean region, which has not yet been explored through drilling. The Asopos-1 exploratory well will test a potential carbonate reservoir at a water depth of 850 meters, reaching a total depth of 4,000 meters below the sea surface.
Background
Block 2 was initially granted to a consortium of Total 50%, Edison 25%, and Hellenic Petroleum (ELPE) 25% in March 2018. In February 2021, Energean Hellas acquired the 50% stake held by Total in Block 2 in the Northwestern Ionian and simultaneously became the Operator of the concession. Through the acquisition of Edison’s hydrocarbon exploration and production division, Energean assumed an additional 25%, bringing its total share of the concession to 75%. A 25% stake in the concession belonged to HelleniQ Upstream Western Corfu (former Hellenic Petroleum Group).
Block 2 is located in the Ionian Sea, 30 km west of Corfu, covering an area of 2,422.1 sq. km. To the west, it extends to the maritime boundary of the Greece–Italy EEZ. Water depths range from 500 m to 1,500 m, and the area belongs to the geological unit of the Pre-Apulia Zone.
Although 3D seismic surveys were not initially planned in the exploration program, following a scientifically substantiated proposal and recommendation from EDEYEP, Energean agreed to upgrade the planned 2D seismic program to a 3D seismic survey. Energean Hellas took over management of Block 2 in February 2021 following EDEYEP’s recommendation and with the approval of the Ministry of Environment and Energy, acquiring Total’s 50% stake and becoming the Operator.
Through the acquisition of Edison’s hydrocarbon exploration and production division, the company assumed an additional 25%, raising its total stake to 75%, with the remaining 25% held by HelleniQ Upstream Western Corfu. This process was completed in record time in December 2021, following immediate actions by EDEYEP and the Ministry of Environment and Energy.
In 2022, the 3D seismic survey was successfully carried out by the research vessel Ramform Hyperion (PGS flagship, now TGS), effectively mapping the entire block. The surveys were conducted with strict environmental protection measures, monitored and confirmed on-site by EDEYEP’s specialized observers.
It is also worth noting that through this survey, the Consortium significantly exceeded the initially agreed minimum financial commitment for exploration in the block, a decision that is now yielding substantial results.
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