Fairfield Energy to Receive $150 Million Equity Investment From Riverstone Holdings to Pursue Growth Opportunities in the North Sea

Staines, Middlesex, UK, and New York, NY (July 5, 2012) – Fairfield Energy, the
private, North Sea-focused independent oil & gas company, has agreed terms for a
major new injection of equity from funds sponsored by Riverstone Holdings LLC, the
energy and power-focused private equity firm. Riverstone will initially make a $150
million equity commitment with the option of subscribing a further $200 million
alongside future contributions from current investors led by Warburg Pincus.

Fairfield Energy was established in late 2005 with the objective of participating in the
anticipated change in ownership of assets held by the traditional North Sea players.
Since then, the Company has built an extensive inventory of exploration and appraisal,
development, and production assets in the Northern North Sea and Southern Gas
Basin. Starting with the acquisition and refurbishment of the Dunlin fields and platform,
Fairfield’s key assets now also include Darwin, Clipper South and Crawford / Porter.
Darwin will see a major programme of exploration and appraisal drilling this year with
three wells planned in partnership with TAQA. The Crawford and Porter discoveries are
progressing to Field Development Plan with EnQuest as operator, and first gas from the
Clipper South development is expected this summer. With Fairfield active in the
27th Round, the foundation is in place to deliver sustained and material growth.

The Riverstone investment will build on the platform provided by this established portfolio. Fairfield management sees significant opportunities in several plays and subbasins in the North Sea, and these require major new investment to advance to full value. To be led jointly by Warburg Pincus and Riverstone, Fairfield’s investors remain committed to the Company’s original vision of building an independent oil & gas company of scale to pioneer this important chapter in the history of the North Sea.

Simon Eyers, Managing Director of Warburg Pincus, speaking on behalf of the existing investor group, said:

“We are delighted to welcome Riverstone as a joint lead investor in Fairfield; their $150 million investment firmly endorses Fairfield’s true potential, marking the launch of a new chapter for the Company and clearly demonstrating how Fairfield is fast evolving as a significant player in the UK North Sea. The progress that Fairfield has made in 2011 and 2012, across the whole portfolio of production, development and exploration assets, is testament to the depth and quality of the team and the real momentum they have given the business. We are excited to be so well positioned to capture theconsiderable value that exists in Fairfield’s current portfolio, as well as in the many new opportunities in the North Sea that the Company will now have access to with the Riverstone investment.”

Pierre Lapeyre and David Leuschen, Co-Founders of Riverstone, said:
“Fairfield is at the forefront of the next generation of North Sea-focused oil & gas
companies. In its relatively short history, the Company has already established a strong
operational track record and positioned itself for growth. Riverstone’s investment will
help Fairfield reach its next stage of development, and we are looking forward to
joining the investor group and supporting Fairfield’s management in maximizing the
value of our investment in the coming months and years.”

In conjunction with the new Riverstone investment, Lord Browne of Madingley,
Riverstone Partner and Ralph Alexander, Managing Director of Riverstone Holdings will
join the Fairfield Board as non-executive directors.

Ron Emerson, Chairman of Fairfield Energy, said:
“We are very pleased to welcome Riverstone as a major new investor and welcome
Lord Browne and Ralph Alexander, who will be joining the board as Riverstone
representatives. They bring significant industry experience and wisdom to the
Company, and we look forward to their contributions. With a strengthened balance
sheet, a quality portfolio and the right team in place, we have an excellent platform and
are very excited about Fairfield’s future as a highly successful exploration and
production company.”