Operations in Second Half of 2014 to Focus on Exploration in the
Putumayo Basin of Colombia and Further Development of the Bretaña Field
in Peru

CALGARY, June 25, 2014 /PRNewswire/ – Gran Tierra Energy Inc. (“Gran Tierra Energy”) (NYSE MKT: GTE, TSX: GTE), a company focused on oil exploration and production in South America,
today announces it has closed the sale of its Argentina business and
provides a corporate update.

“With the successful sale of the Argentina business, Gran Tierra Energy
increases its focus on its exciting exploration and development
drilling campaign in Colombia and Peru in the second half of 2014. We
are currently drilling ahead on the Moqueta-13 development well,
intended to be completed as a production well in the Moqueta field. In
addition, planning is underway to drill four exploration wells in the
second half of 2014 in the Putumayo Basin of Colombia” said Dana
Coffield, Gran Tierra Energy President and Chief Executive Officer. “We
continue to work towards starting long term test production at the
Bretaña field in Peru, anticipated to start in the fourth quarter of
this year, in addition to drilling an appraisal well in the field
before year-end” concluded Coffield.

Argentina

Gran Tierra Energy successfully closed the sale of its Argentina
business to Madalena Energy Inc. (“Madalena”) (TSX-V: MVN) for an
aggregate consideration of approximately US$69 million, comprising
US$49 million in cash, US$14 million in Madalena shares, and expected
working capital adjustments of approximately US$6 million. The
effective date of this transaction is April 30, 2014.

Colombia

Chaza Block, Putumayo Basin (100% Working Interest (“WI”) and Operator)

The Eslabón Sur Shallow-1 and Eslabón Sur Deep-1 exploration wells are
targeting the same Cretaceous Sandstones encountered in the Costayaco
and Moqueta discoveries and are expected to begin drilling in the third
and fourth quarters respectively of 2014.

The Corunta-1A exploration well is expected to spud in the third quarter
of 2014 and will be drilled in a northeast direction from the
Costayaco-17 well pad targeting a downthrown fault block west of the
Moqueta field.

The Moqueta-13 development well was spud on May 25, 2014, and is
drilling in a southeast direction from the Moqueta-1 well pad.
Moqueta-13 is intended to add to the production of the Moqueta field.

Putumayo-1 Block, Putumayo Basin (55% WI and Operator, Compania Espanola
de Petroleos Colombia, S.A.U. 45% working interest)

The Cabañas-1 exploration well is expected to be drilled in the fourth
quarter of 2014 in the Putumayo-1 Block. This block is immediately
south of the Chaza Block in the Putumayo basin where Gran Tierra Energy
encountered multiple explorations successes. The Cabañas-1 well is
targeting the same Cretaceous Sandstones encountered in the Costayaco
and Moqueta discoveries.

Peru

Block 95, Bretaña Field (Gran Tierra Energy 100% WI and Operator)

Planning and construction is underway to initiate drilling of the
Bretaña Sur delineation well in the fourth quarter of 2014 to gather
additional reservoir data and further substantiate oil reserves in the
field.

Work also continues towards starting long term test production at the
Bretaña field at approximately 2,500 barrels of oil per day, which is
anticipated to start in the fourth quarter of this year.

Corporate Update

Production for the months of April and May was consistent with Gran
Tierra Energy’s internal budget and averaged approximately 21,466
barrels of oil equivalent per day (“BOEPD”) net after royalty (“NAR”)
before adjustments for inventory changes despite not having access to
the Ecopetrol-operated Trans-Andean oil pipeline in Colombia (the “OTA
pipeline”) for approximately 28 days during this time period. A recent
landslide has damaged the OTA pipeline, with repairs expected to be
completed in July. During this time, Gran Tierra Energy plans to
transport its oil by truck to continue sales.

With the transaction to sell its Argentina business closed, Gran Tierra
Energy estimates the Argentina business unit contributed average
production of approximately 1,365 BOEPD NAR to its full-year 2014
production estimate. Gran Tierra Energy plans to reduce its 2014
corporate capital spending program by an amount comparable to the
planned Argentina capital program of US$48 million, less the amount
spent up to the closing date of the transaction.

About Gran Tierra Energy Inc.

Gran Tierra Energy is an international oil and gas exploration and
production company, headquartered in Calgary, Canada, incorporated in
the United States, trading on the NYSE MKT (GTE) and the Toronto Stock
Exchange (GTE), and operating in South America. Gran Tierra Energy
holds interests in producing and prospective properties in Colombia,
Peru, and Brazil. Gran Tierra Energy has a strategy that focuses on
establishing a portfolio of producing properties, plus production
enhancement and exploration opportunities to provide a base for future
growth.

Gran Tierra Energy’s Securities and Exchange Commission filings are
available on a web site maintained by the Securities and Exchange
Commission at http://www.sec.gov and on SEDAR at http://www.sedar.com.

Forward Looking Statements and Advisories

This news release contains certain forward-looking information and
forward-looking statements (collectively, “forward-looking statements”)
under the meaning of applicable securities laws, including Canadian
Securities Administrators’ National Instrument 51-102 – Continuous Disclosure Obligations and the United States Private Securities Litigation Reform Act of 1995.
The use of the words “will”, “should”, “planning”, “intended”,
“continue”, “anticipated” and “expected” and derivations thereof and
similar terms identify forward-looking statements. In particular, but
without limiting the foregoing, this news release contains
forward-looking statements regarding: Gran Tierra Energy’s drilling,
testing and production expectations, including without limitation, the
timing of operations, the oil-bearing potential of certain reservoirs
and expectations with respect to drilling locations and depth, the
results of drilling, testing and exploration activities; the timing of
repairs to the OTA pipeline; Gran Tierra Energy’s 2014 production
expectations and projections; and changes to Gran Tierra Energy’s
planned capital program for 2014.

The forward-looking statements contained in this news release reflect
several material factors and expectations and assumptions of Gran
Tierra Energy including, without limitation: that Gran Tierra Energy
will continue to conduct its operations in a manner consistent with
past operations; the accuracy of testing and production results and
seismic data; the effects of certain drilling techniques; cost and
price estimates; and the general continuance of current or, where
applicable, assumed operational, regulatory and industry conditions.
Gran Tierra Energy believes the material factors, expectations and
assumptions reflected in the forward-looking statements are reasonable
at this time but no assurance can be given that these factors,
expectations and assumptions will prove to be correct.

The forward-looking statements contained in this news release are
subject to risks, uncertainties and other factors that could cause
actual results or outcomes to differ materially from those contemplated
by the forward-looking statements, including, among others: Gran Tierra
Energy’s operations are located in South America where unexpected
problems can arise due to guerilla activity and labour disruptions; the
OTA pipeline may continue to experience disruptions and if further
disruptions occur, service at the OTA pipeline may not continue on the
time lines or to the capacity expected by or favorable to Gran Tierra
Energy; attempts to mitigate the effect of disruptions of the OTA
pipeline may not have the impact currently anticipated by Gran Tierra
Energy; unexpected technical difficulties and operational difficulties
may occur, which could impact or delay the completion or continuation
of drilling; geographic, political and weather conditions can interrupt
drilling, which could impact or delay the commencement or continuation
of drilling; the risk that current global economic and credit market
conditions may impact oil prices and oil consumption more than Gran
Tierra Energy currently predicts, which could cause Gran Tierra Energy
to change its current drilling, production and testing plans; and
production data should be considered preliminary until a full well test
interpretation has been done. Further information on potential factors
that could affect Gran Tierra Energy are included in risks detailed
from time to time in Gran Tierra Energy’s Securities and Exchange
Commission filings, including, without limitation, under the caption
“Risk Factors” in Gran Tierra Energy’s Quarterly Report on Form 10-Q
filed May 7, 2014. These filings are available on a Web site maintained
by the Securities and Exchange Commission at http://www.sec.gov and on SEDAR at www.sedar.com. The forward-looking statements contained herein are expressly
qualified in their entirety by this cautionary statement. The
forward-looking statements included in this press release are made as
of the date of this press release and Gran Tierra Energy disclaims any
intention or obligation to update or revise any forward-looking
statements, whether as a result of new information, future events or
otherwise, except as expressly required by applicable securities
legislation.

BOE’s may be misleading, particularly if used in isolation. A BOE
conversion ratio of 6 Mcf: 1 bbl is based on an energy equivalency
conversion method primarily applicable at the burner tip and does not
represent a value equivalency at the wellhead. In addition, given that
the value ratio based on the current price of oil as compared with
natural gas is significantly different from the energy equivalent of
six to one, utilizing a BOE conversion ratio of 6 Mcf: 1 bbl would be
misleading as an indication of value.

SOURCE Gran Tierra Energy Inc.