Endeavour Unveils New Portfolio of US Resource Plays

Company gains significant interests in Haynesville and Marcellus gas shale plays.

HOUSTON, January 6 - Endeavour International Corporation (NYSE Amex: END) (LSE: ENDV)
announced today the acquisition of significant positions in four US resource
plays, including the highly prospective Haynesville and Marcellus gas shale
plays in North Louisiana/East Texas and Western Pennsylvania, respectively,
and new frontier plays in Alabama and Montana. Altogether, Endeavour has
acquired interests in 526,000 gross acres (165,000 net acres) in these four
areas for an approximate US$27 million initial investment.

"These acquisitions represent a major step in Endeavour's strategy to
establish a growth oriented portfolio of onshore properties in the United
States to complement our development and producing assets in the UK," said
William L. Transier, chairman, chief executive officer and president. "We
have gained material positions in the proven Haynesville and Marcellus gas
shale plays as well as new frontier opportunities in Montana and Alabama
where we will be one of the first industry participants. Anticipated
production from these plays combined with our North Sea development projects
has the potential to grow Endeavour's production to meet our previously
stated five-year production goal of 40,000 barrels of oil equivalent per day,
balanced between the US and UK.

"We believe these assets will provide us with a predictable and
sustainable source of growth in reserves and production that will balance the
longer cycle times of our North Sea assets where Endeavour is developing
several large natural gas fields to serve the European market. These new
acreage positions in the United States are also well-balanced between proven
and prospective plays while also providing exposure to oil," Transier added.

Endeavour funded the initial cash contributions for these new joint
ventures from existing cash reserves. Future drilling costs are expected to
be funded from existing cash balances, expanding credit capacity and
potential capital market activity.

Marcellus and Haynesville Plays

Endeavour has entered into a participation agreement with Cohort Energy
Company (a subsidiary of J-W Operating Company) to acquire 50 percent of
Cohort's interests in approximately 66,000 gross (27,000 net) acres in North
Louisiana/East Texas and Western Pennsylvania. Endeavour's initial investment
in the Haynesville and Marcellus gas shale plays is US$15 million, and the
company will pay a share of Cohort's drilling and completion expenditures as
wells are drilled over the next few years. This transaction is in addition to
the acquisition of producing assets from Cohort in North Louisiana and East
Texas previously announced on October 30, 2009.

"This transaction represents the second part of a broad joint venture
Endeavour has established with Cohort and J-W Operating Company," said
Transier. "Cohort has a track record of success as an operator in the Barnett
shale play that will serve us well in the exploitation of these highly
prospective positions in the Haynesville and Marcellus shale plays."

Endeavour could participate in drilling more than 500 horizontal wells
over the next 10 - 15 years in the two resource plays. An overview of our
acreage position and other assumptions relevant to future costs and potential
in each area is as follows:

    Haynesville
    - 17,700 gross acres (7,250 net) - 50 percent held by production
    - 200+ potential drilling locations
    - Average completed well cost: US$8-9 million
    - Average estimated ultimate recovery: 7-8 billion cubic feet (Bcf)
    - Average estimated initial production per well: 15 million cubic feet
      per day
    - Upside potential in Hosston, Cotton Valley and Bossier formations

    Marcellus
    - 48,300 gross acres (19,750 net) - 44 percent held by production
    - 300 + potential drilling locations
    - Average completed well cost: US$3.5 million
    - Average estimated ultimate recovery per well: 3 - 4 billion cubic feet
      (Bcf)
    - Average estimated initial production per well: 3.5 million cubic feet
      per day

Alabama Gas Shale Play

Endeavour has acquired 50 percent of Hillwood Energy Alabama LP's
position in Hillwood's unproven, but highly prospective new multi-target gas
shale play in Alabama. The company's leasehold position covers approximately
160,000 gross acres (63,000 net acres). The initial investment is
approximately US$8.0 million. The companies plan to drill four wells the first
half of 2010 to test this evolving play. If successful, as many as 400 well
locations are available on existing acreage.

"Our venture with Hillwood represents a potential first-mover position
for Endeavour in a frontier gas shale play that extends from more mature
geologic provinces in Alabama and has characteristics of other proven gas
shale plays in the United States," Transier explained. "Hillwood has an
extensive and successful background as a participant and an operator in the
Barnett shale play and we look forward to working with them in the years
ahead in this project and in other areas of the onshore US where similar
opportunities exist."

Montana Shale Play

Endeavour has also acquired 50 percent of the interests owned by a
private company in more than 300,000 gross (75,000 net) acres in central
Montana in a highly prospective, but previously unproven, multiple-reservoir
oil play. Endeavour paid an initial cash consideration of US$3.75 million in
October, 2009.

"This acquisition establishes our position in an oil-prone US frontier
resource area which will also have relatively low appraisal and development
costs. As an oil play, it helps to balance the company's growing
international natural gas position," said Transier. "While the prospectivity
of the play is not well known from drilling activity, the play concept has
been developed over several years by our partner and other industry players
experienced in the region. If proven successful, we could drill as many as
900 wells on the acreage acquired over the next 15 years."

Endeavour International Corporation is an oil and gas exploration and
production company focused on the acquisition, exploration and development of
energy reserves in the North Sea and the United States. For more information,
visit www.endeavourcorp.com.

Certain statements in this news release should be regarded as
"forward-looking" statements within the meaning of the securities laws. These
statements speak only as of the date made. Such statements are subject to
assumptions, risk and uncertainty. Actual results or events may vary
materially. The estimates of recoverable resources per well and completed
well costs included herein are based upon other typical results in these
shale plays and may not be indicative of actual results.

Endeavour - Investor Relations, Mike Kirksey, +44-(0)-207-451-2364, or +1-713-307-8788, or Canaccord Adams - UK Broker, Jeffrey Auld, +44-(0)-207-050-6500; or Pelham, Public Relations - UK Media, Philip Dennis, +44-(0)-207-743-6363, or Henry Lerwill, +44-(0)-203-178-6242