Cobalt International Energy, Inc. Announces Extraordinary Results from Shenandoah Appraisal Well and Provides Update on the

  Cobalt International Energy, Inc. Announces Extraordinary Results from
  Shenandoah Appraisal Well and Provides Update on the North Platte Discovery
  Well, Inboard Lower Tertiary Trend, Deepwater Gulf of Mexico

Business Wire

HOUSTON -- March 19, 2013

Cobalt International Energy, Inc. (“Cobalt”) (NYSE:CIE) today announced
extraordinary results from its Shenandoah #2R appraisal well, located in
Walker Ridge Block 51, and provided an update on its North Platte #1
exploratory well, located in Garden Banks 959, both located in the Inboard
Lower Tertiary Trend, deepwater Gulf of Mexico.

At Shenandoah, the well’s operator announced today that the Shenandoah #2R
appraisal well encountered more than 1,000 net feet of oil pay in multiple
high quality Lower Tertiary-aged reservoirs. Log and pressure data from both
the Shenandoah appraisal well and the 2009 Shenandoah discovery well indicate
the presence of exceptionally high quality reservoirs and hydrocarbons.

The appraisal well was drilled as a straight hole to a total depth of 31,405
feet in approximately 5,800 feet of water, about 1.3 miles southwest and
approximately 1,700 feet structurally down-dip from the Shenandoah #1
discovery well, in order to test the down-dip extent of the Shenandoah field.
Well results indicate that the targeted sands were full to base with no
evidence of oil-water contacts. 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.

Cobalt, as operator, provided an update confirming that the North Platte #1
exploratory well encountered over 550 net feet of oil pay in multiple high
quality Inboard Lower Tertiary reservoirs. This compares to DeGolyer and
MacNaughton’s pre-drill estimate for net pay of 350 feet. North Platte is
located in approximately 4,400 feet of water and was drilled to a total depth
of approximately 34,500 feet. Cobalt completed a bypass coring operation on
North Platte #1 and has since temporarily abandoned the discovery well. In
addition, Cobalt has begun the acquisition of a new state-of-the-art 3D
seismic survey over the greater North Platte field and the majority of its
prospects in the immediate area. Evaluation of this data will be ongoing
throughout 2013. Appraisal plans for North Platte will be determined later in
the year, as well.

Cobalt is currently drilling its Ardennes #1 exploratory well in Green Canyon
896. Ardennes is targeting both Miocene and Inboard Lower Tertiary reservoirs.
Results are expected sometime mid-year 2013. DeGolyer and MacNaughton
estimates Ardennes to have potential resources greater than 500 million
barrels gross oil equivalent.

“The exceptional results of both the Shenandoah #2R appraisal well and the
North Platte #1 exploratory well further substantiate our regional model of
the prolific potential of the Inboard Lower Tertiary Trend,” said Joseph H.
Bryant, Cobalt’s Chairman and Chief Executive Officer. “We believe that our
material working interests in these two significant Inboard Lower Tertiary
fields will be the source of tremendous value for our shareholders. Our deep
portfolio of prospects on trend with these two fields bodes well for our
future growth in the Gulf of Mexico. These recent results and our bright
future are a testament to our commitment to the people and technology required
to succeed in the deepwater Gulf of Mexico subsalt trends.”

Cobalt is the operator and holds a 60 percent working interest in North
Platte. TOTAL E&P USA, INC. (NYSE:TOT) is Cobalt’s partner in North Platte
with a 40 percent working interest. Cobalt is the operator and holds a 42
percent working interest in Ardennes. Partners in Ardennes include
ConocoPhillips (NYSE:COP) (30 percent working interest) and TOTAL E&P USA,
INC. (NYSE:TOT) (28 percent working interest). In Shenandoah, Cobalt holds a
20 percent working interest. Partners in Shenandoah include Anadarko Petroleum
Corporation (NYSE:APC), as operator (30 percent working interest),
ConocoPhillips (NYSE:COP) (30 percent working interest), Venari Resources LLC
(10 percent working interest) and Marathon Oil Company (NYSE:MRO) (10 percent
working interest).

For more information about these announcements, see Cobalt’s March, 2013
Investor Presentation, which can be found on Cobalt's website at in the Investors-Presentations and Publications section.

About Cobalt

Cobalt is an independent oil exploration and production company active in the
deepwater U.S. Gulf of Mexico and offshore Angola and Gabon. Cobalt was formed
in 2005 and is headquartered in Houston, Texas.

Forward-Looking Statements

This press release includes “forward-looking statements” within the meaning of
the safe harbor provisions of the Section 27A of the Securities Act of 1933
and Section 21E of the Securities Exchange Act of 1934 — that is, statements
related to future, not past, events. Forward-looking statements are based on
current expectations and include any statement that does not directly relate
to a current or historical fact. In this context, forward-looking statements
often address Cobalt’s expected future business and financial performance, and
often contain words such as “anticipate,” “believe,” “intend,” “expect,”
“plan,” “will” or other similar words. These forward-looking statements
involve certain risks and uncertainties that ultimately may not prove to be
accurate. Actual results and future events could differ materially from those
anticipated in such statements. For further discussion of risks and
uncertainties, individuals should refer to Cobalt’s SEC filings. Cobalt
undertakes no obligation and does not intend to update these forward-looking
statements to reflect events or circumstances occurring after this press
release, other than as required by law. You are cautioned not to place undue
reliance on these forward-looking statements, which speak only as of the date
of this press release. All forward-looking statements are qualified in their
entirety by this cautionary statement.

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Cobalt International Energy, Inc.
Investor Relations:
Richard A. Smith, +1-713-579-9141
Vice President, Investor Relations, Compliance and Risk Management
Media Relations:
Lynne L. Hackedorn, +1-713-579-9115
Vice President, Government and Public Affairs
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