Carlyle, EBRD agree to sell Black Sea Oil & Gas to Mazarine Energy

By Grace Kim

October 31, 2026

According to Carlyle, Black Sea Oil & Gas and its joint-venture partners invested more than $400 million in the Midia Gas Development project, which now supplies about 12% of Romania’s domestic gas demand.

Mark Beacom, CEO of Black Sea Oil & Gas, said: “Reaching first gas at MGD in 2022 was the result of the willingness and perseverance of the BSOG team and long-term commitment, significant investment and strong support from Carlyle and EBRD.”

He added: “BSOG looks forward to continued success in its efforts in Romania with its new shareholder, Mazarine, which is well placed to further contribute to Romania’s energy security.”

Carlyle and the European Bank for Reconstruction and Development have agreed to sell Black Sea Oil & Gas and BSOG Holding Activity to Mazarine Energy, the companies said. The transaction remains subject to customary regulatory approvals. Mazarine has operated in Romania since 2017.

What is changing hands?

Carlyle said it invested in BSOG in 2015, when the company focused primarily on exploration. The European Bank for Reconstruction and Development has supported BSOG since 2017, the companies said.

The companies said BSOG will continue operating Midia Gas Development after completion. Mazarine will own the business, including an established offshore production platform, while BSOG retains its operating role at the project.

Bob Maguire, co-head of Carlyle International Energy Partners, said: “When Carlyle invested in BSOG in 2015, the company was an exploration-stage business.”

He added: “Over the past decade, BSOG has evolved into Romania’s leading offshore gas producer and an important contributor to domestic energy supply.”

He continued: “The business demonstrates how patient, disciplined private capital can support complex offshore infrastructure, and we are pleased to transfer ownership to Mazarine, which shares our long-term commitment to Romania and its energy sector.”

Ownership changes, but BSOG’s operating role does not; Mazarine is acquiring a working gas business rather than taking over day-to-day operations.

What has BSOG built?

During Carlyle’s ownership, BSOG and its joint-venture partners invested more than $400 million in Midia, Carlyle said. The project became the first offshore hydrocarbon production hub developed in the Romanian Black Sea in more than 30 years.

Carlyle said the development included:

• The offshore Ana production platform.
• A 126-kilometer subsea pipeline.
• A new onshore gas treatment facility in Vadu.

Natural gas production began in June 2022. Since then, Midia has supplied approximately 12% of Romania’s domestic gas demand, the companies said. BSOG owns a 70% interest in the project and serves as its operator.

The companies said Midia has strengthened Romania’s domestic energy supply amid heightened concerns about energy security across Europe.

Midia is already producing at scale, and BSOG’s 70% operating stake gives Mazarine exposure to an established local asset.

What can grow next?

According to the companies, BSOG is pursuing additional opportunities around its infrastructure and offshore holdings. Those include:

• Potential carbon capture and storage development within the Midia block.
• Offshore wind opportunities that could use BSOG’s existing energy corridor and land assets.
• Biomethane projects being developed through wholly owned subsidiary BSOG Energy.

The acquisition expands Mazarine’s presence in Romania and gives it ownership of an established offshore production platform, with additional potential across conventional and lower-carbon energy projects, the companies said.

Jefferies served as financial adviser to Carlyle on the transaction.

The growth case extends beyond producing gas, although the announcement describes the CCS and wind opportunities as potential and the biomethane work as projects under development.

How do the buyer and EBRD frame the deal?

Guido Funes Nova, co-head of Carlyle International Energy Partners, said: “With significant remaining resources, as well as the carbon capture and storage (“CCS”) development potential in the Midia block and a pipeline of biomethane projects, we believe BSOG has a strong platform for long-term growth, supported by the proven strength of its organization.”

Edward van Kersbergen, CEO of Mazarine Energy, said: “Romania has been a core part of Mazarine’s business since 2017, and we are proud to build on that presence with BSOG.”

He added: “MGD is a major achievement for the country’s energy security, and we want to build on what the BSOG team has accomplished and contribute to Romania’s energy security for years to come.”

He thanked: “We thank Carlyle and the EBRD for their trust and look forward to working with the BSOG team, our partners and the Romanian authorities.”

Victoria Zinchuk, EBRD regional head of Romania, Bulgaria and Greece, said: “BSOG’s development into Romania’s leading offshore gas producer is a significant achievement.”

She added: “Since the EBRD invested in 2017, the company has brought an important offshore resource into production, contributing to the diversification and security of Romania’s energy supply.”

She concluded: “This is a strong example of how long-term investment can support private-sector development while delivering benefits for the wider economy.”

The buyer and EBRD both frame BSOG as a long-term Romanian platform, with current gas production providing the base for new projects.

Regulatory clearance is the next gate for the ownership transfer. After closing, Mazarine’s case rests on preserving Midia’s roughly 12% contribution to Romanian gas demand while BSOG advances CCS, offshore wind and biomethane opportunities around its existing assets.