EXECUTION
VERSION

    


    AMENDMENT
NO. 1 TO CREDIT AGREEMENT

     

    This
AMENDMENT NO. 1 TO CREDIT AGREEMENT (this “Amendment”) is
entered into as of January 1, 2009, by and among GRAN TIERRA ENERGY COLOMBIA,
LTD., a Utah limited partnership (Registered No. 2110646-0180) (the “Partnership”), ARGOSY
ENERGY, LLC, a Delaware limited liability company (f/k/a Argosy Energy Corp., a
Delaware corporation) (Registered No. 3234977) (the “GP”), GRAN TIERRA
ENERGY INC., a Nevada corporation (Registered No. C13734-2003) (the “Borrower”), and
STANDARD BANK PLC as the Majority Bank (as defined in the Credit Agreement
referred to below) and the Administrative Agent (as defined in the Credit
Agreement referred to below).

     

    WHEREAS,
the Partnership, the GP, the Borrower, the Majority Bank and the Administrative
Agent are parties to that certain Credit Agreement, dated as of February 22,
2007 (as amended, amended and restated, supplemented or otherwise modified from
time to time, the “Credit
Agreement”);

     

    WHEREAS,
the Borrower is the direct and beneficial owner of all of the issued and
outstanding membership interests of the GP and 99.2857% of the issued and
outstanding partnership interests of the Partnership;

     

    WHEREAS,
pursuant to a corporate reorganization (the “Restructuring”), the
GP converted from a Delaware corporation into a Delaware limited liability
company;

     

    WHEREAS,
pursuant to the Restructuring, the Borrower desires to transfer all of its
interests in the Partnership and the GP to GTE Colombia Holdings LLC, a Delaware
limited liability company (the “LLC”), in exchange
for membership interests in the LLC;

     

    WHEREAS,
pursuant to the Restructuring, the LLC desires to issue all of its limited
liability interests in nine separate series (each a “Series”) pursuant to
the laws of Delaware, each Series to hold 100% of the interest in one of nine
properties directly held by the Partnership, whereby six Series will be retained
by the Borrower and three Series will be contributed to Gran Tierra Energy
Cayman Islands Inc., a newly formed corporation organized as a wholly-owned
Subsidiary of the Borrower under the laws of the Cayman Islands (“Cayman
One”);

     

    WHEREAS,
pursuant to the Restructuring, Cayman One desires to organize Gran Tierra Energy
Cayman Islands II Inc. as a new Subsidiary under the laws of the Cayman Islands
(“Cayman Two”)
and Cayman Two desires to organize Gran Tierra Energy Canada ULC as a new
Subsidiary under the laws of the Province of Alberta, Canada (the “ULC”);
and

     

    WHEREAS,
the Administrative Agent and Majority Bank have agreed to consent to the
consummation of the foregoing transactions (collectively, the “Specified
Transactions”) pursuant to the terms and subject to the conditions set
forth below.

     

    NOW,
THEREFORE, in consideration of the foregoing premises and mutual covenants
herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, each of the parties hereto hereby
agree as follows:


    
      
         


      

      
         


        
          

        

      

      
         


      

    


    Section
1.               Definitions.  Unless
the context otherwise requires, capitalized terms used but not defined herein
shall have the meanings given to them in the Credit Agreement.

     

    Section
2.               Waiver and
Consent.

     

    2.1           Consents.  Subject
to the satisfaction of the conditions precedent set forth in Section 4 of this
Amendment, each of the Administrative Agent and the Majority Bank hereby
consents to the consummation of the Specified Transactions.

     

    2.2           Waivers.  The
Majority Bank hereby waives any Default or Event of Default which arose or may
arise as a result of any failure by the Borrower to meet obligations under
Sections 9.03(a), 9.05, 9.08, 9.13 and 9.15 of the Credit Agreement, and any
term or condition of any other Loan Document, solely to the extent such failure
is due to the consummation of all or any part of the Specified
Transactions.  The Majority Bank hereby additionally waives the
requirements under Section 9.16 of the Credit Agreement that (a) the LLC, Cayman
One, Cayman Two and the ULC become Subsidiary Guarantors and Obligors under the
Credit Agreement and (b) the Borrower and Cayman Two pledge their interests in
the LLC, in each case for so long as Gran Tierra Energy Inc., a Nevada
corporation (Registered No. C13734-2003) remains the Borrower under the Credit
Agreement.  It is hereby acknowledged and agreed that the foregoing
waivers shall not be deemed to be, nor construed as, a waiver of any other
Default or Event of Default that may now be in existence or that may hereafter
occur.

     

    Section
3.               Amendments to Credit
Agreement.

     

    3.1           Amendments to
Preamble.

     

    (a)           The
preamble of the Credit Agreement is hereby amended by deleting the reference to
“GRAN TIERRA ENERGY INC., a corporation organized under the laws of the State of
Nevada (Registered No. E0666052005-8)” and replacing it with “GRAN TIERRA ENERGY
INC., a corporation organized under the laws of the State of Nevada (Registered
No. C13734-2003)”.

     

    (b)           The
preamble of the Credit Agreement is hereby amended by deleting and replacing
references to “T2R OB2” with “T2R 0B2”.

     

    3.2           Amendment to Definition of
“Security Documents”.  Section 1.01 of the Credit Agreement is
hereby amended by amending and restating the definition of “Security Documents”
in its entirety as follows:

     

    “Security Documents”
shall mean, collectively, the Canadian Pledge Agreement, the Colombian Security
Documents, the Collection Account Pledge Agreement, the GP Pledge Agreement, the
Partnership Pledge Agreement and each of the security agreements, pledge
agreements and other instruments now or hereafter delivered to the
Administrative Agent pursuant to the foregoing or otherwise granting a Lien on
any Property of any Person to secure the obligations and liabilities of any
Obligor under any Loan Document, and all other filings required by applicable
law to be filed with respect to the security interests created pursuant to each
of the foregoing documents.


    
      
         


      

      
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    3.3           Amendment to Section
9.  Section 9 of the Credit Agreement is hereby amended by
adding the following Section 9.26:

     

    9.26                      Activities of Holding
Companies.  Each of GTE Colombia Holdings LLC, a Delaware
limited liability company (the “LLC”), Gran Tierra
Energy Cayman Islands Inc., a corporation organized under the laws of the Cayman
Islands (“Cayman
One”), Gran Tierra Energy Cayman Islands II Inc., a corporation organized
under the laws of the Cayman Islands (“Cayman Two”), Gran
Tierra Energy Canada ULC, an unlimited liability company organized under the
laws of the Province of Alberta, Canada (the “ULC”), and any entity
directly owning or holding Capital Stock in the GP or the Partnership shall not
(a) conduct, transact or otherwise engage in, or commit to conduct, transact or
otherwise engage in, any material business or operations other than (i) holding
(A) with respect to the LLC only, the Capital Stock of the GP or the Partnership
and their respective Subsidiaries, (B) with respect to Cayman One only, the
Capital Stock of the LLC and Cayman Two, and (C) with respect to Cayman Two
only, the Capital Stock of the ULC, (ii) performing its obligations and
activities under its organizational documents, (iii) with respect to Cayman Two
only, acting as general manager of the LLC and as manager of the series of
limited liability interests in the LLC established pursuant to Section 18-215 of
the Delaware Limited Liability Act, 6 Del. C. § 18-101, et seq., as amended from time
to time, (iv) issuing its own Capital Stock subject to the terms hereof, (v)
preparing reports to its equity holders, (vi) holding board of directors and
equity holders meetings, preparing partnership, corporate or limited liability
company records and other partnership, corporate or limited liability company
activities required to maintain its separate partnership, corporate or limited
liability company structure or to comply with applicable requirements of law or
the terms of its organizational documents, and (vii) activities and assets
incidental to the foregoing clauses (i) through (vi); (b) incur, create, assume
or suffer to exist any Indebtedness or other liabilities or financial
obligations; (c) incur, create, assume or suffer to exist any Lien upon any of
its property, whether now owned or hereafter acquired, other than pursuant to
the Loan Documents; (d) own, lease, manage or otherwise operate any material
properties or assets; or (e) directly own assets constituting an operating
business; provided that the
foregoing shall not prevent (x) the LLC, Cayman One, Cayman Two or the ULC from
complying with any obligation under that certain participation agreement, dated
as of June 22, 2006 (as amended through December 30, 2008, and as further
amended from time to time, so long as each such further amendment is not, taken
as a whole, materially adverse to the Banks, the “Participation
Agreement”), by and among the Partnership, the Borrower and Crosby
Capital LLC, or (y) the ULC from acting as an employer and engaging in and
performing such activities incidental thereto.

     

    Section
4.               Conditions
Precedent.  The waiver referred to in Section 2.1 shall become
effective as of the date first above written, provided that on or
before such date:

     

    (a)           this
Amendment shall have been executed by the Partnership, the GP, the Borrower and
the Majority Bank and counterparts hereof as so executed shall have been
delivered to the Administrative Agent;


    
      
         


      

      
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    (b)           the
LLC shall have executed and delivered to the Administrative Agent a pledge
agreement governed by the laws of the State of New York, dated as of the date
hereof, substantially in the form of the GP Pledge Agreement in effect prior to
the date hereof, granting in favor of the Administrative Agent for the ratable
benefit of the Secured Parties a first-priority security interest in all of the
interests in the GP;

     

    (c)           the
GP and the LLC shall have executed and delivered to the Administrative Agent a
pledge agreement governed by the laws of the State of New York, dated as of the
date hereof, substantially in the form of the Partnership Pledge Agreement in
effect prior to the date hereof, granting in favor of the Administrative Agent
for the ratable benefit of the Secured Parties a first-priority security
interest in all of the interests in the Partnership;

     

    (d)           the
Administrative Agent shall have received, and be reasonably satisfied in form
and substance with, a legal opinion from Cooley Godward Kronish LLP, Delaware
and New York counsel to the GP and the LLC; and

     

    (e)           both
before and immediately after giving effect to this Amendment and the
consummation of the Specified Transactions, all of the representations and
warranties set forth in Section 5 below will
be true and correct.

     

    Section
5.               Miscellaneous

     

    5.1           Representations and
Warranties.  Each Obligor, by signing below, hereby represents
and warrants to the Administrative Agent and the Banks that:

     

    (a)           each
Obligor is duly organized, validly existing and in good standing (if such
concept exists under the laws of its jurisdiction of organization) under the
laws of its jurisdiction of organization;

     

    (b)           the
execution, delivery, and performance of this Amendment and the consummation of
the transactions contemplated hereby (i) are within their limited partnership,
limited liability company or corporate powers, as applicable, (ii) have been
duly authorized by all necessary limited partnership, limited liability company
or corporate action, as applicable, (iii) do not conflict with its
constitutional documents or any applicable law or any of its contractual
obligations except for any such conflict with applicable laws or contractual
obligations that would not have a Material Adverse Effect, and (iv) will not
result in the creation or imposition of any Lien prohibited by the Credit
Agreement;

     

    (c)           no
consent, authorization, or approval of, and except for filings and recordings in
respect of the Liens created pursuant to the Security Documents and except for
customary 8-K filings, no filings and registrations with, any Governmental
Authority, or any securities exchange, is necessary for the execution and
delivery of this Amendment or the performance of its obligations
hereunder;


    
      
         


      

      
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    (d)           each
Obligor has executed and delivered this Amendment, and upon satisfaction of the
conditions set forth in Section 4 above, this Amendment constitutes a legal,
valid, and binding obligation, enforceable against each Obligor in accordance
with its terms, except as such enforceability may be limited by any applicable
bankruptcy, insolvency, reorganization, moratorium, or similar laws affecting
creditors’ rights generally and by general principles of equity (regardless of
whether such enforceability is considered in a proceeding in equity or at
law);

     

    (e)           both
before and after giving effect to this Amendment, no Default or Event of Default
(for the avoidance of doubt, other than that contemplated pursuant to Section
2.2 above) has occurred and is continuing or is reasonably expected to occur
immediately following the consummation of the transactions contemplated by this
Amendment; and

     

    (f)           to
the extent not already made above, each of the other representations and
warranties set forth in Section 8 of the Credit Agreement is true and correct in
all material respects as of the date hereof after giving effect to this
Amendment (unless stated to relate solely to an earlier date, in which case such
representation or warranty shall be true and correct as of such earlier
date).

     

    5.2           Expenses.  As
provided in the Credit Agreement, but without limiting any terms or provisions
thereof, each Obligor agrees to pay on demand, upon presentation of a statement
of account, all reasonable and documented out-of-pocket costs and expenses
incurred by the Administrative Agent in connection with the preparation,
negotiation, and execution of this Amendment, including without limitation the
reasonable fees and expenses of the Administrative Agent’s legal counsel,
regardless of whether this Amendment becomes effective in accordance with the
terms hereof.

     

    5.3           Waiver of
Claims.  Each Obligor hereby waives and releases each of the
Secured Parties and their respective directors, officers, employees, attorneys,
affiliates and subsidiaries from any and all claims, offsets, defenses and
counterclaims of which such Obligor is aware that currently exist and can now be
asserted to reduce or eliminate all or any part of the obligation of each
Obligor to make any payments to the Secured Parties as provided in the Loan
Documents, such waiver and release being made with full knowledge and
understanding of the circumstances and effect thereof and after having consulted
legal counsel with respect thereto.  Each of the Partnership and the
GP further agrees and acknowledges that its guarantee obligations under Section
6 of the Credit Agreement shall remain in full force and effect and shall be
unaffected by the terms of this Amendment.

     

    5.4           Credit Agreement
Unaffected.  Each reference to the Credit Agreement in any Loan
Document shall hereafter be construed as a reference to the Credit Agreement as
amended hereby.  Except as herein otherwise specifically provided, all
provisions of the Credit Agreement and the other Loan Documents shall remain in
full force and effect and be unaffected hereby.  This Amendment is a
Loan Document.

     

    5.5           Entire
Agreement.  This Amendment, together with the Credit Agreement
and the other Loan Documents constitute the entire agreement among the parties
with respect to the subject matter hereof, the Credit Agreement and such other
Loan Documents and supersede all prior agreements and understandings, both oral
and written, between the parties with respect to the subject matter
hereof.


    
      
         


      

      
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    5.6           Counterparts.  This
Amendment may be executed in any number of counterparts, all of which taken
together shall constitute one and the same instrument and any of the parties
hereto may execute this Amendment by signing any such counterpart, including by
facsimile or pdf (with an original subsequently delivered).

     

    5.7           Governing
Law.  THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE
PARTIES HEREUNDER SHALL BE CONSTRUED AND INTERPRETED IN ACCORDANCE WITH AND BE
GOVERNED BY THE LAW OF THE STATE OF NEW YORK.

     

    5.8           Submission to
Jurisdiction.  EACH PARTY HEREBY IRREVOCABLY CONSENTS TO THE
NON-EXCLUSIVE JURISDICTION OF THE UNITED STATES DISTRICT COURT FOR THE SOUTHERN
DISTRICT OF NEW YORK AND OF ANY NEW YORK STATE COURT SITTING IN THE BOROUGH OF
MANHATTAN, NEW YORK CITY FOR THE PURPOSE OF ANY LEGAL PROCEEDINGS ARISING OUT
OF, UNDER, OR IN CONNECTION WITH, THIS AMENDMENT OR THE TRANSACTIONS
CONTEMPLATED HEREBY.

     

    5.9           Jury Trial
Waiver.  EACH PARTY HEREBY IRREVOCABLY WAIVES, TO THE FULLEST
EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT TO A TRIAL BY JURY IN ANY
LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS AMENDMENT OR THE
TRANSACTIONS CONTEMPLATED HEREBY.  EACH PARTY ACKNOWLEDGES AND AGREES
THAT IT HAS RECEIVED FULL AND SUFFICIENT CONSIDERATION FOR THIS PROVISION AND
THAT THIS PROVISION IS A MATERIAL INDUCEMENT FOR THE PARTIES TO ENTER THIS
AMENDMENT.

     

    [Signature
page follows.]


    
      
         


      

      
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    IN
WITNESS WHEREOF, this Amendment has been duly executed and delivered as of the
date first above written.

     

    
      
        
          
            	 
      	
                    OBLIGORS

                  
	 
      	 
      
	 
      	
                    GRAN
      TIERRA ENERGY INC.

                  
	 
      	 
      
	 
      	
                    By:

                  	           
      /s/ Martin Eden
	 
      	 
      	
                    Name:
      Martin Eden

                  
	 
      	 
      	
                    Title:   Chief
      Financial Officer

                  
	 
      	 
      
	 
      	
                    ARGOSY
      ENERGY, LLC

                  
	 
      	
                    (f/k/a
      Argosy Energy Corp.)

                  
	 
      	 
      
	 
      	
                    By:

                  	
                    Gran
      Tierra Energy Cayman Islands II, Inc.,

                  
	 
      	 
      	
                    its
      Manager

                  


          

        

      

    

    


    
      
        
          	 
      	
                  By:

                	           
      /s/ Martin Eden
	 
      	 
      	
                  Name:
      Martin Eden

                
	 
      	 
      	
                  Title:   Chief
      Financial Officer

                
	 
      	 
      


        

      

    

    


    
      
        	 
      	
                GRAN
      TIERRA ENERGY COLOMBIA, LTD.

              
	 
      	 
      
	 
      	
                By:

              	
                Argosy
      Energy, LLC (f/k/a Argosy Energy

                Corp.),
      its General Partner

              


      

    

    


    
      
        	 
      	
                By:

              	
                Gran
      Tierra Energy Cayman Islands II,

                Inc.,
      its Manager

              


      

    

    


    
      
        
          	 
      	
                  By:

                	           
      /s/ Martin Eden
	 
      	 
      	
                  Name:
      Martin Eden

                
	 
      	 
      	
                  Title:   Chief
      Financial Officer

                
	 
      	 
      	 
      


        

      

    

     

    
      Amendment
No. 1 to Credit Agreement

       

    

    
      
         


      

      
         


        
          

        

      

      
         


      

    

    


    
      
        
          
            
              
                	 
      	
                        MAJORITY BANK

                      
	 
      	 
      
	 
      	
                        STANDARD
      BANK PLC

                      
	 
      	 
      
	 
      	
                        By:

                      	            /s/
      Martin Revoredo
	 
      	 
      	
                        Name:
      Martin Revoredo

                      
	 
      	 
      	
                        Title:   Senior
      Vice President

                      
	 
      	 
      
	 
      	
                        By:

                      	           
      /s/ Roderick L. Fraser
	 
      	 
      	
                        Name:
      Roderick L. Fraser

                      
	 
      	 
      	
                        Title:  
      Managing Director, Global Head of Energy
Finance

                      


              

            

          

        

      

    

    


    
      
        
          
            
              
                	 
      	
                        ADMINISTRATIVE AGENT

                      
	 
      	 
      
	 
      	
                        STANDARD
      BANK PLC

                      
	 
      	 
      
	 
      	
                        By:

                      	            /s/
      Martin Revoredo
	 
      	 
      	
                              
                          Name:
      Martin Revoredo

                        

                      
	 
      	 
      	
                              
                          Title:   Senior
      Vice President

                        

                      
	 
      	 
      
	 
      	
                        By:

                      	           
      /s/ Roderick L. Fraser
	 
      	 
      	
                              
                          Name:
      Roderick L. Fraser

                        

                      
	 
      	 
      	
                              
                          Title:  
      Managing Director, Global Head of Energy
    Finance

                        

                      
	 
      


              

            

          

        

      

    

     

    
      Amendment
No. 1 to Credit Agreement