Exhibit 4.28





EXECUTION VERSION

























Amendment
agreement No. 2



relating to a pre-payment agreement dated
18 December 2015, as amended by an amendment agreement no. 1 dated 1 September 2016















Dated	                             December 2016



















GeoPark Colombia S.A.S.



(the Seller)



C.I. Trafigura Petroleum Colombia S.A.S.



(the Buyer)



GeoPark Ltd.



(the Guarantor)

















Amendment
agreement No. 2 (the Agreement)



Dated	
                       December
2016



Between



| | (1) | GeoPark
                                         Colombia S.A.S., a company incorporated under the laws of Colombia whose registered
                                         office is at Calle 94 No. 11-30 8th Floor, Bogota, Colombia (the Seller);
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (2) | C.I.
                                         Trafigura Petroleum Colombia S.A.S., a company incorporated under the laws of Colombia
                                         whose registered office is at Carrera 11 No. 82-01 Of. 701, Bogota, Colombia (the Buyer);
                                         and
| | --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (3) | GeoPark
                                         Ltd.,a company incorporated under the laws of Bermuda whose registered office is
                                         at Cumberland House, 9th Floor, 1 Victoria Street, Hamilton HM11, Bermuda
                                         with registration number 33273 (the Guarantor).
| | --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



Recitals



| | A | This
                                         Agreement is supplemental to and amends a facility agreement dated 18 December 	2015,
                                         as amended by an amendment agreement no. 1 dated 1 September 2016, between, among others,
                                         the Seller, the Buyer and the Guarantor (thePrepayment
                                         Agreement).
| | - | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | B | The
                                         Parties have agreed to make certain amendments to the Prepayment Agreement on the terms
                                         of this Agreement and to provide certain confirmations in respect of the Transaction
                                         Documents.
| | - | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



It is
agreed:



| | 1 | Definitions
                                         and construction
| | - | ---------------------------------------------------------------------



| | 1.1.1 | Definitions
| | ----- | -----------



Words
and expressions defined in the Prepayment Agreement, as amended by this Agreement, shall have the same meanings in this Agreement.
In addition:



Amendment
Effective Date means the date on which the Buyer notifies the Seller that it has received all the documents and evidence listed
in the Schedule, each in form and substance satisfactory to it.



| | 1.1.2 | Construction
| | ----- | ------------



The
principles of construction set out in clause 1.2 (Interpretation) of the Prepayment Agreement shall apply to this
Agreement, insofar as they are relevant to it, as they apply to the Prepayment Agreement.



| | 1.1.3 | Third
                                         party rights
| | ----- | -----------------------------------------------------------



The
provisions of clause 1.3 (Third party rights) of the Prepayment Agreement shall apply to this Agreement as they apply
to the Prepayment Agreement.



Page 2





| | 2 | Amendments
| | - | ----------



With
effect from the Amendment Effective Date, the Prepayment Agreement shall be amended as follows.



| | 2.1.1 | Clause
                                         2.1 paragraph (a) of the Prepayment Agreement shall be deleted in its entirety and replaced
                                         with the following:
| | ----- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



“(a)
Subject to paragraph (c) below and the other terms of this Agreement the Buyer makes available to the Seller the Advances up to
and including the end of the Availability Period in an aggregate amount not exceeding (i) for the period from the Signing Date
to and including the Initial Commitment Period End Date, the Initial Commitment; and (ii) for the period commencing from and including
the day after the Initial Commitment Period End Date to and including the end of the Availability Period, the Reduced Commitment.”



| | 2.1.2 | Clause
                                         6.3 of the Prepayment Agreement shall be deleted in its entirety and replaced with the
                                         following:
| | ----- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



“In
addition to any deductions or reimbursements payable by the Seller to the Buyer under Clauses 6.1 and 6.2, the Seller shall reimburse
the Buyer by way of a cash payment, such amounts required to ensure that the Outstanding Advances from and after the first day
following the end of the Availability Period do not, subject always to the reimbursement obligations of the Seller in respect
of the Outstanding Advances and each Reimbursement Instalment as set out in this Agreement (and in particular Clauses 6.1 and
6.2), exceed US$60,000,000.”.



| | 2.1.3 | The
                                         definition of ‘Availability Period’ set out in Schedule 2 (Definitions)
                                         of the Prepayment Agreement shall be deleted in its entirety and replaced with the following:
| | ----- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



“Availability
Periodmeans the period from and including the Signing Date, to and including 30 June 2017, or such later date as may
be agreed by the Buyer in its sole and absolute discretion”.



| | 2.1.4 | The
                                         definition of ‘Commitment’ set out in Schedule 2 (Definitions) of
                                         the Prepayment Agreement shall be deleted in its entirety and replaced with the following:
| | ----- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



“Commitmentmeans, as applicable, the Initial Commitment, the Reduced Commitment or the Additional Advance;”.



| | 2.1.5 | The
                                         definition of ‘Initial Commitment’ set out in Schedule 2 (Definitions)
                                         of the Prepayment Agreement shall be deleted in its entirety and replaced with the following:
| | ----- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



“Initial
Commitmentmeans the principal amount of US$67,500,000, to the extent not cancelled or reduced under this Agreement;”.



| | 2.1.6 | The
                                         definition of ‘Maximum Commitment’ set out in Schedule 2 (Definitions)
                                         of the Prepayment Agreement shall be deleted in its entirety and replaced with the following:
| | ----- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



“Maximum
Commitment means the principal amount of US$67,500,000, to the extent not cancelled or reduced under this Agreement;”.



Page 3





| | 2.1.7 | The
                                         following definitions of “Initial Commitment Period End Date”, “Signing
                                         Date” and “Reduced Commitment” shall be inserted at Schedule 2 of the
                                         Prepayment Agreement:
| | ----- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



“Initial
Commitment Period End Datemeans 31 March 2017;”;



“Reduced
Commitmentmeans the principal amount of US$65,000,000, to the extent not cancelled or reduced under this Agreement;”;
and



“Signing
Datemeans 18 December 2015”.



| | 3 | Confirmations
| | - | -------------



| | 3.1.1 | Without
                                         prejudice to the rights of the Buyer which have arisen on or before the date of this
                                         Agreement or the Amendment Effective Date, each of the Seller and the Guarantor confirm,
                                         that, on and after the date of this Agreement and the Amendment Effective Date:
| | ----- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (a) | the
                                         Prepayment Agreement (as amended by this Agreement), and the other Transaction Documents
                                         (to which they are a party), will remain in full force and effect; and
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (b) | the
                                         Security Documents (to which they are a party) will:
| | --- | -------------------------------------------------------------------------------------------------



| | (i) | not
                                         be affected by this Agreement and will continue in full force and effect to the extent
                                         not replaced, ratified or supplemented as contemplated by this Agreement, subject to
                                         any limitations set out in the Security Documents;
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (ii) | extend
                                         to the liabilities and obligations of the Seller and the Guarantor as laid out in the
                                         Prepayment Agreement (as amended by this Agreement); and
| | ---- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (iii) | include
                                         as obligations of the Seller and the Guarantor any additional indebtedness incurred and
                                         other obligations under the Prepayment Agreement as amended by this Agreement.
| | ----- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 3.1.2 | The
                                         Guarantor confirms that, on and after the date this Agreement, its guarantee, set out
                                         at clause 13 of the Prepayment Agreement (the Guarantee) will remain in full force
                                         and effect and will extend to the Seller’s obligations under the Prepayment Agreement
                                         (as amended by this Agreement).
| | ----- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 4 | Representations
                                         and warranties
| | - | -----------------------------------------------------------------------



The
representations and warranties set out in clause 14 (Representations and warranties) of the Prepayment Agreement are deemed
to be repeated by both the Seller and the Guarantor by reference to the facts and circumstances then existing on the date of this
Agreement and the Amendment Effective Date.



| | 5 | Further
                                         action
| | - | -------------------------------------------------------



The
Seller and the Guarantor shall, at their own expense, promptly take any action and sign or execute any further documents which
the Buyer may require in order to give effect to the requirements of this Agreement.



| | 6 | Counterparts
| | - | ------------



This
Agreement may be executed in any number of counterparts, and this has the same effect as if the signatures on the counterparts
were on a single copy of this Agreement.



Page 4





| | 7 | Governing
                                         law and enforcement
| | - | ----------------------------------------------------------------------



| | 7.1.1 | Governing
                                         Law
| | ----- | ------------------------------------------------------



This
Agreement, its interpretation and any non-contractual obligations arising from or connected with it, is governed by and shall
be construed in accordance with English law.



| | 7.1.2 | Enforcement
| | ----- | -----------



The
provisions of paragraph 29 (Dispute Resolution and Jurisdiction) of the Prepayment Agreement shall apply to this Agreement
as they apply to the Prepayment Agreement.



This Agreement
has been entered into on the date stated at the beginning of this Agreement.



Page 5





Schedule



Conditions
precedent to the Amendment Effective Date



| | 1. | This
Agreement, duly executed by all the parties to it.
| | -- | -------------------------------------------------------



| | 2. | Any
other document or evidence required by the Buyer in connection with this Agreement and the transactions contemplated by this Agreement.
| | -- | -------------------------------------------------------------------------------------------------------------------------------------------



Page 6





Execution
Pages





|The Seller                                                                                                                                                      |  |                              |                      | 
|--------------------------------------------------------------------------------------------------------------------------------------------------------------- |  | ---------------------------- | -------------------- | 
|                                                                                                                                                                |  |                              |                      | 
|Executed by GeoPark
    Colombia S.A.S..as the Seller and signed by person(s) who under the laws of Colombia are acting under the authority of
    that company |  | /s/ Carlos
    Bolaños Ortiz |                     
|                                                                                                                                                                |  | Name:                        | Carlos Bolaños Ortiz | 
|                                                                                                                                                                |  | Position:                    | Legal Representative | 
|                                                                                                                                                                |  |                              |                      | 
|                                                                                                                                                                |  | /s/ Marcela Vaca Torres      |                     
|                                                                                                                                                                |  | Name:                        | Marcela Vaca Torres  | 
|                                                                                                                                                                |  | Position:                    | Legal Representative | 







|The Buyer                                                                                                                                                                   |  |                      |                      | 
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |  | -------------------- | -------------------- | 
|                                                                                                                                                                            |  |                      |                      | 
|Executed by C.I. Trafigura Petroleum Colombia S.A.S.
    as the Buyer and signed by person(s) who under the laws of Colombia are acting under the authority of that company |  | /s/ Nicolas Daguerre |                     
|                                                                                                                                                                            |  | Name:                | Nicolas Daguerre     | 
|                                                                                                                                                                            |  | Position:            | Legal Representative | 
|                                                                                                                                                                            |  |                      |                      | 
|                                                                                                                                                                            |  | /s/ Emilio Comotti   |                     
|                                                                                                                                                                            |  | Name:                | Emilio Comotti       | 
|                                                                                                                                                                            |  | Position:            | Power of Attorney    | 







|The Guarantor                                                                                                                                      |  |                            |                        | 
|-------------------------------------------------------------------------------------------------------------------------------------------------- |  | -------------------------- | ---------------------- | 
|                                                                                                                                                   |  |                            |                        | 
|Executed by Geopark Ltd. as the Guarantor and signed
    by person(s) who under the laws of Bermuda are acting under the authority of that company |  | /s/ Pedro Aylwin Chiorrini |                       
|                                                                                                                                                   |  | Name:                      | Pedro Aylwin Chiorrini | 
|                                                                                                                                                   |  | Position:                  | Legal Representative   | 







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