Chevron joins Helleniq in Eastern Mediterranean offshore block

June 17, 2026, by Melisa Cavcic

U.S.-headquartered energy giant Chevron has signed on the dotted line to acquire a majority stake and operatorship in a block off the coast of Greece, currently solely owned by Helleniq Energy, a Greek integrated energy player.

Man with a hardhat with words "Chevron" on it with an offshore rig in the background — Illustration; Source: Chevron

The agreement with Helleniq will enable Chevron to participate in the Block 10 concession, located offshore the Kyparissiakos Gulf in the Southern Ionian Sea in Greece. Under the terms of the deal, the U.S. firm will acquire a 70% participating interest in the concession and assume the role of operator, while the Greek company will retain a 30% stake.

Andreas Shiamishis, Helleniq Energy’s CEO, commented: “Chevron’s entry into Block 10 further strengthens our existing partnership and aligns the interests of both companies across all blocks in the Southern Ionian, creating a significantly larger exploration area in which we jointly participate. Flexibility within our portfolio, along with the ability to operate across a broader acreage position, are key factors in attracting leading international energy companies and unlocking potential synergies.

“The work we have undertaken in Block 10 in recent years has enabled a more comprehensive assessment of its potential and supported Chevron’s entry into the wider portfolio. The adjustment of our participating interest reflects our strategy of actively managing our exploration assets as a dynamic portfolio, where ownership and structures can evolve in response to changing conditions.”

Block 10 is currently in its second exploration phase, where both 2D and 3D seismic studies have been completed, providing a more advanced understanding of the subsurface and supporting the evaluation of potential future drilling targets.

As exploration activity progresses, the partnership is expected to focus on further de-risking the asset through additional technical evaluation and potential drilling phases, in line with the broader development of Greece’s offshore exploration sector.

Andrew Deighan, Director, Exploration, Middle East and North Africa, Chevron, remarked: “This is another key milestone for Chevron as we continue to build momentum in the Mediterranean region, an area where we are looking to further expand and strengthen our global exploration portfolio.

“Together with our partner, Helleniq Energy, and the Hellenic Republic, we are looking forward to evaluating the hydrocarbon potential of Block 10, which is in an exciting frontier area.”

Helleniq claims that this agreement marks a further expansion of one of the most significant exploration partnerships currently developing in the Eastern Mediterranean, underscoring both companies’ commitment to unlocking the potential of the country’s offshore energy resources.

The partnership combines Chevron’s technical and operational capabilities with the Greek player’s established domestic portfolio, supporting a balanced approach to risk-sharing while maintaining exposure to future exploration upside.

Deighan emphasized: “Chevron has significant expertise in developing oil and gas projects globally. We believe that the combination of our partner’s expertise and support coupled with our resources and technology, will help to advance and unlock new energy supplies in this region.”

Chevron, which expanded its presence in Greece’s hydrocarbon exploration portfolio since last year, now participates in five offshore concessions together with Helleniq.