EXECUTION
VERSION

    


    RELEASE
OF PARTNERSHIP PLEDGE AGREEMENT

     

    This
RELEASE OF PARTNERSHIP PLEDGE AGREEMENT, dated as of January 1, 2009 (this
“Release”), is
by and among GRAN TIERRA ENERGY INC., a Nevada corporation (Registered No.
C13734-2003) (the “Borrower”), ARGOSY
ENERGY, LLC, a Delaware limited liability company (f/k/a Argosy Energy Corp., a
Delaware corporation) (Registered No. 3234977) (the “Guarantor”, together
with the Borrower, each a “Pledgor” and,
collectively, the “Pledgors”), and
STANDARD BANK PLC, as administrative agent under the Credit Agreement (as
hereinafter defined) acting for and on behalf of the Secured Parties (as defined
in the Credit Agreement) (in such capacity, the “Pledgee”).

     

    WHEREAS,
the Borrower is the limited partner of, and direct and beneficial owner of
99.2857% of the issued and outstanding partnership interests of, GRAN TIERRA
ENERGY COLOMBIA, LTD., a Utah limited partnership (Registered No. 2110646-0180)
(the “Issuer”);

     

    WHEREAS,
the Guarantor is the general partner of, and direct and beneficial owner of
0.7143% of the issued and outstanding partnership interests of, the
Issuer;

     

    WHEREAS,
in order to secure its obligations under and in connection with 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”),
among the Borrower, the Guarantor, the Issuer, certain of their affiliates, the
banks from time to time party thereto and the Pledgee, the Pledgors entered in
that certain Partnership Pledge Agreement, dated as of February 22, 2007 (the
“Partnership Pledge
Agreement”), granting a security interest in the Pledged Property (herein
defined as defined in the Partnership Pledge Agreement);

     

    WHEREAS,
pursuant to a corporate reorganization (the “Restructuring”), the
Borrower proposes to transfer its interest in the Pledged Property to GTE
Colombia Holdings LLC (the “LLC”) and whereupon,
the LLC, together with the Guarantor, shall execute and deliver to the Pledgee a
pledge agreement (as the same may be amended, restated, substituted or
supplemented from time to time, the “LLC Pledge
Agreement”) governed by the laws of the State of New York, dated on the
date hereof, substantially in the form of the Partnership Pledge Agreement,
granting in favor of the Pledgee for the ratable benefit of the Secured Parties
a first-priority security interest in all of the Pledged Property;

     

    WHEREAS,
the Pledgee has agreed to consent to the consummation of the Restructuring and,
in connection therewith, to release the security interest in the Pledged
Property created under the Partnership Pledge Agreement, pursuant to the terms
and subject to the conditions set forth below;

     

    NOW,
THEREFORE, in consideration of the foregoing premises 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.                      Release of Security
Interest.  Solely in order to facilitate the Restructuring and
subject to the Pledgors’ performance of their undertakings under Section 2
below, the Pledgee hereby releases and terminates its security interest granted
under the Partnership Pledge Agreement in the Pledged Property.  The
Pledgee shall execute and deliver to the Pledgors all releases or other
documents, including, without limitation, Uniform Commercial Code (“UCC”) amendment or
termination statements, reasonably necessary or desirable for the release of the
security interest on the Pledged Property.

    


    
      
        
           


        

        
           


          
            

          

        

        
           


        

      

    

     

    Section
2.                      LLC Pledge
Agreement.  The Borrower hereby undertakes to cause the LLC,
and the Guarantor hereby undertakes, to execute and deliver to the Pledgee the
LLC Pledge Agreement promptly upon the consummation of the
Restructuring.  Notwithstanding the foregoing, if the Restructuring is
not effective or the LLC and Guarantor fail to execute and deliver to the
Pledgee the LLC Pledge Agreement, the Pledgors shall immediately re-execute and
deliver to the Pledgee a pledge agreement substantially in the form of the
Partnership Pledge Agreement, granting in favor of the Pledgee for the ratable
benefit of the Secured Parties a first-priority security interest in all of the
Pledged Property.

     

    Section
3.                      Binding
Effect.  This Release and all of the provisions hereof shall be
binding upon each party hereto and their respective successors and
assigns.

     

    Section
4.                      Governing Law, Waivers and
Consents.

     

    (a)           The
validity, interpretation and enforcement of this Release and any dispute arising
out of the relationship between the Pledgors and the Pledgee or any Secured
Party, whether in contract, tort, equity or otherwise, shall be governed by the
laws of the State of New York, including, without limitation, Section 5-1401 of
the New York General Obligations Law.

     

    (b)           The
Pledgors hereby irrevocably consent and submit to the non-exclusive jurisdiction
of the Supreme Court of the State of New York, sitting in the Borough of
Manhattan, the City of New York and the United States District Court for the
Southern District of New York, whichever the Pledgee may elect, and waive any
objection based on venue or forum non conveniens with respect to any action
instituted therein arising under this Release or in any way connected with or
related or incidental to the dealings of the Pledgors and the Pledgee or any
Secured Party in respect of this Release or the transactions related hereto or
thereto, in each case whether now existing or hereafter arising, and whether in
contract, tort, equity or otherwise, and agrees that any dispute with respect to
any such matters shall be heard only in the courts described above.

     

    (c)           Each
Pledgor hereby irrevocably consents to the service of process out of any of the
courts mentioned in Section 4(b) above in any such action or proceeding by the
mailing of copies thereof by registered or certified mail, postage prepaid to
such Pledgor at its respective address referred to in Section 12.02 of the
Credit Agreement.

     

    (d)           EACH
PLEDGOR HEREBY WAIVES ANY RIGHT TO TRIAL BY JURY OF ANY CLAIM, DEMAND, ACTION OR
CAUSE OF ACTION (i) ARISING UNDER THIS RELEASE OR ANY OF THE OTHER LOAN
DOCUMENTS OR (ii) IN ANY WAY CONNECTED WITH OR RELATED OR INCIDENTAL TO THE
DEALINGS OF THE PARTIES HERETO OR THERETO IN RESPECT OF THIS RELEASE OR THE
TRANSACTIONS RELATED HERETO OR THERETO IN EACH CASE WHETHER NOW EXISTING OR
HEREAFTER ARISING, AND WHETHER IN CONTRACT, TORT, EQUITY OR
OTHERWISE.  EACH PLEDGOR HEREBY AGREES AND CONSENTS THAT ANY SUCH
CLAIM, DEMAND, ACTION OR CAUSE OF ACTION SHALL BE DECIDED BY COURT TRIAL WITHOUT
A JURY AND THAT THE PLEDGORS, ANY SECURED PARTY OR THE PLEDGEE MAY FILE AN
ORIGINAL COUNTERPART OF A COPY OF THIS RELEASE WITH ANY COURT AS WRITTEN
EVIDENCE OF THE CONSENT OF THE PLEDGORS TO THE WAIVER OF ITS RIGHT TO TRIAL BY
JURY.

    


    
      
        
           


        

        
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    Section
5.                      Further
Assurances.  Each party hereto agrees that it will, at any time
and from time to time, upon the written request of any other party, execute and
deliver such further documents and do such further acts and things, as the
requesting party may reasonably request in order to effect the purposes of this
Release; provided that any
such action undertaken by the Pledgee shall be at the sole cost and expense of
the Pledgors.

     

    Section
6.                      Counterparts.  This
Release may be executed in counterparts (and by different parties hereto on
different counterparts), each of which shall constitute an original, but all of
which when taken together shall constitute a single
contract.  Delivery of an executed counterpart of a signature page of
this Release by facsimile or electronic copy shall be effective as delivery of a
manually executed counterpart of this Agreement.

     

    [Signature
page follows.]

     

    
      
        
        

      

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

     

    
      
        
          
            
              
                	
                        PLEDGORS

                      
	 
      
	 
      
	
                        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

                      


              

            

          

        

      

    

    
       

      Release
of Partnership Pledge Agreement

    

    
      
        
           


        

        
           


          
            

          

        

        
           


        

      

    

    


    
      
        
          	
                  PLEDGEE

                
	 
      	 
      
	
                  STANDARD
      BANK PLC,

                
	
                  as
      Bank and as administrative agent for the

                  Secured
      Parties

                
	 
      	 
      
	 
      	 
      
	
                  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

                  

                


        

      

    

     

    Release of Partnership Pledge
Agreement