Implementation Agreement

Gulf Keystone Petroleum Ld
22 May 2007



Not for release, publication or distribution in or into jurisdictions other than
the United Kingdom and Bermuda where to do so would constitute a contravention
of the relevant laws of such jurisdiction


                     Amendment to Implementation Agreement


Gulf Keystone announces that yesterday it entered into an amendment agreement 
("Amendment Agreement") with RAK Petroleum amending the terms of the Algerian
Material Adverse Change termination clause set out in the Implementation
Agreement.


The effect of the Amendment Agreement is to amend the provisions under which the
occurrence of an Algerian Material Adverse Change (as defined below) would give
rise to the right for RAK Petroleum to terminate the Implementation Agreement,
the Amalgamation Agreement and the Amalgamation after the date of the Special
General Meeting of the Company (the "SGM").


Under the terms of the Amendment Agreement, RAK Petroleum will have the right to
terminate the Implementation Agreement, the Amalgamation Agreement and the
Amalgamation if an Algerian Material Adverse Change occurs between 13 April 2007
and the date which falls 5 Business Days after the date that the Management
Committee (Conseil de Gestion), in accordance with the relevant provision of and
within the time limits set forth in the Block 126a PSC, declares the GKN and GKS
fields commercially exploitable in accordance with the Final Discovery Report
(as defined below), as evidenced by the unanimously signed minutes of the
relevant meeting of the Management Committee.


The definition of an Algerian Material Adverse Change has been amended to now
mean: "any event, occurrence, or change of circumstance specifically relating to
Algeria (excluding (i) the reports or results from any currently planned well
testing being carried out by Gulf Keystone, (ii) war or terrorism and (iii)
official written notification of a change in the fiscal regime applicable to the
Algerian Assets which represents a material adverse change to the laws and
decrees as published in Algeria at the date of the Amendment Agreement) which
individually or together with other events, occurrences or circumstances in
Algeria, has or is reasonably likely to have a material adverse effect on Gulf
Keystone's Algerian business or on the Algerian Assets (such as RAK Petroleum
having become aware of any Materially Adverse Information regarding the
validity, ownership, or scope of the Hydrocarbon Rights or Gulf Keystone's
currently pending application for the declaration of commerciality in respect of
the GKN and GKS fields)".


The definition of Final Discovery Report has been amended to mean: "the Final
Discovery Report dated January 2007 as Disclosed as amended and finally
submitted to the Management Committee (Conseil de Gestion) in a form
substantially similar to the Final Discovery Report dated January 2007 as
Disclosed taking into account all necessary changes to reflect the passage of
time from January 2007 until the date of final submission (such as for example
the start date of first oil production)".

The Acquisition remains subject to a number of other conditions, which are
summarised in paragraph 2 of Part III of the Circular distributed to Gulf
Keystone Shareholders on 13 April 2007 and are set out in full in Appendix B to
the Circular.


The SGM is being held today at the offices of Cox Hallett Wilkinson, Milner
House, 18 Parliament Street, Hamilton, Bermuda at 1.00pm Bermuda time (5.00pm
London time) to, inter alia, approve the Amalgamation Resolution.

Subject to the satisfaction or waiver of all conditions, the Amalgamation is
currently anticipated to be completed by no later than 11 August 2007.


Unless otherwise stated, defined terms used in this Announcement shall have the
same meaning as those used in the Circular posted to Gulf Keystone Shareholders
on 13 April 2007.


Enquiries:


Gulf Keystone Petroleum                  [phone]
Bill Guest
Todd Kozel
Jon Cooper


Citigate Dewe Rogerson                   [phone]

Media enquiries: Martin Jackson

Analyst enquiries: Nina Soon


This Announcement does not constitute an offer to sell or the solicitation of an
offer to subscribe for or buy any security, nor is it a solicitation of any vote
or approval in any jurisdiction, nor shall there be any sale, issuance or
transfer of the securities referred to in this Announcement in any jurisdiction
in contravention of applicable law.


This Announcement has been prepared for the purposes of complying with English
and Bermuda law and information disclosed in it may not be the same as that
which would have been prepared in accordance with the laws of jurisdictions
outside England or Bermuda.


                      This information is provided by RNS
            The company news service from the London Stock Exchange