Marathon Oil Announces Shenandoah Appraisal Well Results

Marathon Oil Announces Shenandoah Appraisal Well Results

Well Encounters More Than 1,000 Net Feet of Oil Pay

HOUSTON, March 19, 2013 (GLOBE NEWSWIRE) -- Marathon Oil Corporation (NYSE:
MRO) today announced the Shenandoah-2 well in the deepwater Gulf of Mexico has
encountered more than 1,000 net feet of oil pay in multiple high-quality Lower
Tertiary-aged reservoirs.

The Shenandoah-2 well, located in Walker Ridge block 51, was drilled to a
total depth of 31,405 feet in approximately 5,800 feet of water, more than 1
mile southwest and approximately 1,700 feet structurally down-dip from the
Shenandoah-1 discovery. Similar to the initial Shenandoah discovery well, log
and pressure data from the Shenandoah-2 well indicate excellent-quality
reservoir and fluid properties. The well was drilled to test the down-dip
extent of the accumulation, and the targeted sands were full to base with no
oil-water contact.

The Shenandoah-1 discovery  well was  drilled in  early 2009  on Walker  Ridge 
Block 52 and encountered more than 300 net feet of Inboard Lower Tertiary  oil 
pay.

The operator and partners are incorporating the information obtained from
Shenandoah-2 into planning and anticipate further appraisal drilling to
advance this potentially significant resource discovery.

Marathon Oil holds a 10 percent working interest in Shenandoah. Partners
include Anadarko Petroleum Corporation as operator (30 percent working
interest), ConocoPhillips (30 percent working interest), Cobalt International
Energy, L.P. (20 percent working interest), and Venari Resources LLC (10
percent working interest).

Marathon Oil Corporation is an international exploration and production
company. Based in Houston, Texas, the Company had net proved reserves at the
end of 2012 of 2 billion barrels of oil equivalent in North America, Europe
and Africa. For more information, please visit our website at
http://www.marathonoil.com.

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This release contains forward-looking statements related to the possibility of
a new resource base and expectations for further appraisal drilling. These
statements are based on current expectations, estimates and projections and
are not guarantees of future performance. Actual results may differ
materially from these expectations, estimates and projections and are subject
to certain risks, uncertainties and other factors, some of which are beyond
the Company's control and difficult to predict. In accordance with the "safe
harbor" provisions of the Private Securities Litigation Reform Act of 1995,
Marathon Oil Corporation has included in its Annual Report on Form 10-K for
the year ended December 31, 2012, cautionary language identifying other
important factors, though not necessarily all such factors, that could cause
future outcomes to differ materially from those set forth in the
forward-looking statements.

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