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                                                                    Exhibit 99.9

                           Standby Purchase Agreement

September 6, 2002


Lyford Investments Enterprises Ltd.
720 5/th/ Ave., 9/th/ Floor
New York, New York 10019
Attention: Mr. Alan Quasha


Gentlemen:

         Harken Energy Corporation, a Delaware corporation (the "Company"),
proposes to offer up to 95,238,085 shares of the Common Stock, par value $0.01
per share (the "Common Stock"), of the Company, initially for subscription upon
the exercise of rights (the "Rights") evidenced by non-transferable subscription
certificates (the "Subscription Certificates") to be issued by the Company to
holders of shares of Common Stock of the Company of record at the close of
business on or about November 1, 2002 (the actual date the Board of Directors of
the Company establishes such date hereinafter referred to as the "Record Date")
(all shares issuable upon the exercise of Rights by holders of Common Stock
shall be referred to as the "Shares").

         The Rights will expire at 5:00 P.M., New York City time, on or about
December 20, 2002 (the actual date and time on which the Rights expire, the
"Expiration Date"). The Company proposes to sell to Lyford Investments
Enterprises Ltd. ("Purchaser"), a number of Shares which, as of the Expiration
Date, have not been subscribed for by the holders of Common Stock by the
exercise of Rights (the "Securities"). The Company's obligation to sell and
deliver the Securities to Purchaser shall be contingent on Purchaser's
performance of its obligations under this Agreement. The issuance of the Rights,
the offering of the Common Stock to be issued by the Company upon exercise of
the Rights and the subscription and purchase of Common Stock upon the terms
described in the Prospectus (as hereinafter defined), including the purchase of
the Securities pursuant to this Agreement, are herein collectively referred to
as the "Rights Offering." The Rights Offering shall be contingent upon approval
thereof by the stockholders of the Company at the Annual Meeting of Stockholders
presently scheduled to be held on November 19, 2002.

         1.   Representations and Warranties.

         (a)  The Company represents and warrants to, and agrees with, Purchaser
as set forth below in this Section 1(a). Certain terms used in Section 1 are
defined in paragraphs (i) and (xix) of this Section 1(a).

              (i) The Company meets the requirements for use of Form S-3 under
         the Securities Act of 1933, as amended (the "Act"). The Company will
         file with the Securities and Exchange Commission (the "Commission") a
         registration statement on such Form for the registration under the Act
         of the offering of the Rights and the offering and sale of the
         Securities. The Company will file with the Commission either (A) prior
         to effectiveness of such registration statement, a further amendment to
         such registration statement (including the form of a final prospectus)
         or (B) after effectiveness of such registration statement, a final
         prospectus in accordance with Rule 424(b). In the case of clause (B),
         the Company shall include in such registration statement, as amended at
         the Effective Date, all information required by the Act and the rules
         thereunder to be included in the

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         Prospectus with respect to the Rights, the Securities and the offering
         thereof. As filed, such amendment and the form of final prospectus, or
         such final prospectus, shall contain all required information with
         respect to the Rights, the Securities and the offering thereof and,
         except to the extent Purchaser shall agree in writing to a
         modification, shall be in all substantive respects in the form
         furnished to Purchaser prior to the Execution Time or, to the extent
         not completed at the Execution Time, shall contain only such specific
         additional information and other changes as the Company has advised
         Purchaser, prior to the Execution Time, will be included or made
         therein.

                  The form of prospectus to be used in connection with the
         offering of the Rights and the offering and sale of the Securities as
         first filed pursuant to Rule 424(b) or, if no filing pursuant to Rule
         424(b) is required, such form of prospectus included in the
         Registration Statement at the Effective Date, is hereinafter called the
         "Prospectus." The Prospectus and any related letters from the Company
         to record or beneficial owners of Common Stock or Rights, related
         letters from the Company to securities dealers, commercial banks, trust
         companies and other nominees and other offering materials, in each case
         disseminated by the Company or by any of its agents with the Company's
         prior consent, including, without limitation, the Certificates for
         Subscription Rights, the Instructions as to Use of Rights Certificates,
         the Notices of Guaranteed Delivery, the Form of Letter to the Holders
         of Common Stock, and information that the Company may use or authorize
         for use in connection with the Rights Offering, are collectively
         referred to hereinafter as the "Offering Materials." Capitalized terms
         used herein without definition have the meanings assigned to them in
         the Prospectus.

                  (ii)  On the Effective Date, the Registration Statement will,
         and when the Prospectus is first filed (if required) in accordance with
         Rule 424(b) and on the Closing Date (as hereinafter defined), the
         Prospectus (and any supplements thereto) will, comply in all material
         respects with the applicable requirements of the Act and the Securities
         Exchange Act of 1934, as amended (the "Exchange Act"), and the
         respective rules thereunder; on the Effective Date, the Registration
         Statement will not contain any untrue statement of a material fact or
         omit to state any material fact required to be stated therein or
         necessary in order to make the statements therein not misleading; and
         on the Effective Date, the Prospectus, if not required to be filed
         pursuant to Rule 424(b), and the Offering Materials did not or will
         not, and on the date of any filing pursuant to Rule 424(b) and on the
         Closing Date, the Prospectus (together with any supplement thereto) and
         the Offering Materials will not, include any untrue statement of a
         material fact or omit to state a material fact necessary in order to
         make the statements therein, in the light of the circumstances under
         which they were made, not misleading; provided, however, that the
         Company makes no representations or warranties as to the information
         contained in or omitted from the Registration Statement or the
         Prospectus (or any supplement thereto) in reliance upon and in
         conformity with information furnished in writing to the Company by or
         on behalf of Purchaser or relating to Purchaser or its affiliates
         specifically for inclusion in the Registration Statement or the
         Prospectus (or any supplement thereto).

                  (iii) The Company has all requisite corporate power and
         authority to execute, deliver and perform its obligations under this
         Agreement; and this Agreement has been duly authorized, executed and
         delivered by the Company and, assuming due execution and delivery of
         this Agreement by Purchaser, constitutes a legal, valid and binding
         obligation of the Company, enforceable against the Company in
         accordance with its terms except (A) as enforcement thereof may be
         limited by applicable bankruptcy, insolvency, reorganization or other
         similar laws affecting creditors' rights generally and except as
         enforcement thereof is subject to general principles of equity
         (regardless of whether enforcement is considered in a proceeding in
         equity or at law), and (B) as rights to indemnity and contribution
         hereunder may be limited by Federal or state securities law and/or
         public policy.

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                  (iv)   Ernst & Young LLP, which has reported upon the audited
         financial statements incorporated by reference in the Registration
         Statement and the Prospectus, is an independent public accountant as
         required by the Act and the Exchange Act.

                  (v)    The consolidated financial statements and the related
         notes of the Company incorporated by reference in the Registration
         Statement and the Prospectus present fairly in accordance with
         generally accepted accounting principles the consolidated financial
         position of the Company as of the dates indicated and the consolidated
         results of operations and cash flows of the Company for the periods
         specified. Such financial statements have been prepared in conformity
         with generally accepted accounting principles applied on a consistent
         basis throughout the periods involved, except as otherwise noted
         therein and subject, in the case of interim statements, to normal
         year-end audit adjustments.

                  (vi)   The Company is a corporation duly organized, validly
         existing and in good standing under the laws of the State of Delaware
         with full corporate power and corporate authority under such laws to
         own, lease and operate its properties and conduct its business as
         described in the Registration Statement and the Prospectus. The Company
         is duly qualified to transact business as a foreign corporation and is
         in good standing in each other jurisdiction in which it owns or leases
         property of a nature, or transacts business of a type, that would make
         such qualification necessary, except to the extent that the failure to
         so qualify or be in good standing would not have a material adverse
         effect on the Company and its subsidiaries, considered as one
         enterprise.

                  (vii)  All of the outstanding shares of capital stock of the
         Company have been duly authorized and validly issued and are fully paid
         and non-assessable; no holder thereof is or will be subject to personal
         liability by reason of being such a holder; and none of the outstanding
         shares of capital stock of the Company was issued in violation of the
         preemptive rights of any stockholder of the Company.

                  (viii) The outstanding shares of Common Stock, the Rights, the
         Subscription Certificates and the Securities conform in all material
         respects to the descriptions thereof contained or incorporated by
         reference in the Registration Statement and the Prospectus.

                  (ix)   The Company had, at the date indicated, the
         stockholders' equity set forth in the Consolidated Balance Sheets
         contained in the Company's Annual Report on Form 10-K for the fiscal
         year ended December 31, 2001.

                  (x)    Prior to or at the Effective Date, the Company will
         have entered into a subscription agency agreement (the "Subscription
         Agency Agreement") with a subscription agent (the "Subscription
         Agent"), which Subscription Agent shall act on behalf of the Company in
         connection with, among other things, the issuance, exercise, sale and
         transfer of Rights as part of the Rights Offering. When executed by the
         Company, the Subscription Agency Agreement will have been duly
         authorized, executed and delivered by the Company and, assuming due
         authorization, execution and delivery by the Subscription Agent, will
         constitute a valid and binding obligation of the Company, enforceable
         against the Company in accordance with its terms, except as enforcement
         thereof may be limited by bankruptcy, insolvency, reorganization or
         other similar laws affecting creditors' rights generally and except as
         enforcement thereof is subject to general principles of equity
         (regardless of whether enforcement is considered in a proceeding in
         equity or at law).

                  (xi)   The Rights, when issued and delivered in accordance
         with the terms of the Rights Offering, will be validly issued, and no
         holder thereof is or will be subject to personal liability by reason of
         being such a holder; the shares of Common Stock issuable upon the
         exercise of the Rights

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         and the Securities, when issued or delivered and paid for in accordance
         with the terms of the Rights Offering, will be validly issued, fully
         paid and non-assessable, and no holder thereof is or will be subject to
         personal liability by reason of being such a holder; and the issuance
         of the shares of Common Stock issuable upon the exercise of the Rights
         and the Securities will not be subject to the preemptive rights of any
         stockholder of the Company.

                  (xii)  The Company has taken all valid corporate action to
         duly reserve such number of its authorized and unissued shares of
         Common Stock as are deliverable upon consummation of purchases pursuant
         to the Rights Offering.

                  (xiii) Since the respective dates as of which information is
         given in the Registration Statement and the Prospectus, except as
         otherwise stated or described therein, contemplated thereby, or
         incorporated by reference therein, there has not been (i) any material
         adverse change in the condition (financial or otherwise), results of
         operations, earnings, business affairs or business prospects of the
         Company, whether or not arising in the ordinary course of business, or
         (ii) any dividend or distribution of any kind declared, paid or made by
         the Company on its capital stock other than the Rights.

                  (xiv)  Except as otherwise stated in the Prospectus or the
         documents incorporated by reference therein, none of the Company or any
         of its subsidiaries is in violation of its certificate of incorporation
         or in default in the performance or observance of any obligation,
         agreement, covenant or condition contained in any contract, indenture,
         mortgage, loan agreement, note, lease or other agreement or instrument
         to which it is a party or by which it may be bound or to which any of
         its properties may be subject, except for such defaults that in the
         aggregate would not have a material adverse effect on the condition
         (financial or otherwise), results of operations, earnings, business
         affairs or business prospects of the Company and its subsidiaries
         considered as one enterprise. The execution and delivery of this
         Agreement, the issuance and delivery of the Rights and the Securities,
         the consummation of the Rights Offering and the consummation by the
         Company of the transaction contemplated in this Agreement, the
         Registration Statement and the Prospectus, and compliance by the
         Company with terms of this Agreement do not and will not result in any
         violation of the charter or by-laws of the Company, and do not and will
         not conflict with, or result in a breach of any of the terms or
         provisions of, or constitute a default under, or result in the creation
         or imposition of any lien, charge or encumbrance upon any property or
         assets of the Company or any of its subsidiaries under (A) any
         indenture, mortgage, loan agreement, note, lease or other agreement or
         instrument to which the Company or any of its subsidiaries is a party
         or by which each of them or any of them may be bound or to which any of
         their respective properties may be subject or (B) any existing
         applicable law, rule, regulation, judgment, order or decree of any
         government, governmental instrumentality or court, domestic or foreign,
         having jurisdiction over the Company or any of its subsidiaries or any
         of their respective properties (except, in the case of (A) and (B)
         above, where such conflicts, breaches or defaults or liens, charges or
         encumbrances in the aggregate would not have a material adverse effect
         on the condition (financial or otherwise), results of operations,
         earnings, business affairs or business prospects of the Company and its
         subsidiaries considered as one enterprise).

                  (xv)   Except as otherwise disclosed in the Prospectus or the
         documents incorporated by reference therein, no authorization,
         approval, consent or license of any government, governmental
         instrumentality or court, domestic or foreign (other than under the Act
         and the securities or blue sky law of the various states), is required
         for the offer of the Rights, the offer and sale by the Company of
         Securities, the consummation of the Rights Offering as set forth in the
         Registration Statement and the Prospectus or the consummation by the
         Company of the transactions contemplated in this Agreement and in the
         Registration Statement and the Prospectus.

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                  (xvi)   Except as disclosed in the Prospectus or the documents
         incorporated by reference therein, there is no action, suit or
         proceeding before or by any government, governmental instrumentality or
         court, domestic or foreign, now pending or, to the knowledge of the
         Company, threatened against or affecting the Company or any of its
         subsidiaries, that is required to be disclosed in the Registration
         Statement and the Prospectus. There are no contracts or documents of a
         character required to be described in the Registration Statement or the
         Prospectus or to be filed as exhibits to the Registration Statement or
         the Prospectus that are not described and filed as required.

                  (xvii)  The Securities, when issued, will be authorized for
         listing on the American Stock Exchange, subject only to official notice
         of issuance.

                  (xviii) The proceeds of the Rights Offering will be applied as
         set forth in the Prospectus. The Rights Offering shall have no
         over-subscription privilege.

                  (xix)   The terms which follow, when used in this Agreement,
         shall have the meanings indicated. "Effective Date" shall mean the date
         that the Registration Statement becomes effective. "Execution Time"
         shall mean the date and time that this Agreement is executed and
         delivered by the parties hereto. "Registration Statement" shall mean
         the registration statement referred to in paragraph (i) above,
         including exhibits and financial statements, as amended at the
         Execution Time (or, if not effective at the Execution Time, in the form
         in which it shall become effective) and, in the event any
         post-effective amendment thereto becomes effective prior to the Closing
         Date, shall also mean such registration statement as so amended. "Rule
         424" refers to such rule under the Act. Any reference herein to the
         Registration Statement or the Prospectus shall be deemed to refer to
         and include the documents incorporated by reference therein which were
         filed under the Exchange Act on or before the Effective Date of the
         Registration Statement or the issue date of the Prospectus and any
         reference herein to the terms "amend," "amendment" or "supplement" with
         respect to the Registration Statement or the Prospectus shall be deemed
         to refer to and include the filing of any document under the Exchange
         Act after the issue date of the Prospectus deemed to be incorporated
         therein by reference.

         (b)      Purchaser represents and warrants to, and agrees with, the
                  Company as set forth below in this Section 1(b).

                  (i)     Purchaser has all requisite partnership power and
         authority to execute, deliver and perform its obligations under this
         Agreement; and this Agreement has been duly authorized, executed and
         delivered by Purchaser and, assuming due execution and delivery of this
         Agreement by the Company, constitutes a legal, valid and binding
         obligation of Purchaser, enforceable against Purchaser in accordance
         with its terms except (A) as enforcement thereof may be limited by
         applicable bankruptcy, insolvency, reorganization or other similar laws
         affecting creditors' rights generally and except as enforcement thereof
         is subject to general principles of equity (regardless of whether
         enforcement is considered in a proceeding in equity or at law), and (B)
         as rights to indemnity and contribution hereunder may be limited by
         Federal or state securities laws and/or public policy.

                  (ii)    To the extent that the Registration Statement contains
         any information concerning Purchaser, on the Effective Date the
         Registration Statement did or will, and when the prospectus is first
         filed (if required) in accordance with Rule 424(b) and on the Closing
         Date (as hereinafter defined), the Prospectus (and any supplements
         thereto) will, comply in all material respects with the applicable
         requirements of the Act and the Exchange Act and the respective rules
         thereunder with respect to such information; to the extent that the
         Registration Statement contains any information

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         concerning Purchaser, on the Effective Date, the Registration Statement
         did not or will not contain any untrue statement of a material fact or
         omit to state any material fact required to be stated therein or
         necessary in order to make the statements therein not misleading with
         respect to such information; and on the Effective Date, to the extent
         that the Registration Statement contains any information concerning
         Purchaser, the Prospectus, if not required to be filed pursuant to Rule
         424(b), did not or will not, and on the date of any filing pursuant to
         Rule 424(b) and on the Closing Date, the Prospectus (together with any
         supplement thereto) will not, include any untrue statement of a
         material fact or omit to state a material fact necessary in order to
         make the statements therein, in the light of the circumstances under
         which they were made, not misleading with respect to such information.

                  (iii) The execution and delivery of this Agreement, the
         purchase of the shares of Common Stock to be purchased by Purchaser
         hereunder, the consummation by Purchaser of the transactions
         contemplated in this Agreement, the Registration Statement and the
         Prospectus and compliance by Purchaser with the terms of this Agreement
         do not and will not result in any violation of the memorandum or
         articles of association of Purchaser, and do not and will not conflict
         with, or result in a breach of any of the terms or provisions of, or
         constitute a default under, or result in the creation or imposition of
         any lien, charge or encumbrance upon any property or assets of
         Purchaser or any of its subsidiaries under (A) any indenture, mortgage,
         loan agreement, note, lease or other agreement or instrument to which
         Purchaser or any of its subsidiaries is a party or by which each of
         them or any of them may be bound or to which any of their respective
         properties may be subject or (B) any existing applicable law, rule,
         regulation, judgment, order or decree of any government, governmental
         instrumentality or court, domestic or foreign, having jurisdiction over
         Purchaser or any of its subsidiaries or any of their respective
         properties (except, in the case of (A) and (B) above, where such
         conflicts, breaches or defaults or liens, charges or encumbrances in
         the aggregate would not have a material adverse effect on the condition
         (financial or otherwise), results of operations, earnings, business
         affairs or business prospects of Purchaser and its subsidiaries
         considered as one enterprise).

                  (iv)  Except as otherwise disclosed in the Prospectus, no
         authorization, approval, consent or license of any government,
         governmental instrumentality or court, domestic or foreign (other than
         under the Act and the securities or blue sky laws of the various
         states) is required for the purchase of the shares of Common Stock to
         be purchased by Purchaser hereunder as set forth in the Registration
         Statement and the Prospectus and the consummation by Purchaser of the
         transactions contemplated in this Agreement and in the Registration
         Statement and the Prospectus.

                  (v)   Described in Schedule 1 hereto are any plans or
         proposals which the Purchaser may have in regard to the Company and its
         governance.

         2.       Purchase and Sale; Option to Purchase Shares of Common Stock.
Subject to the terms and conditions and in reliance upon the representations and
warranties herein set forth, the Company agrees to sell to Purchaser, and
Purchaser agrees to purchase from the Company at a purchase price per share
equal to the subscription price per share specified in the Registration
Statement a number of shares of Common Stock (the "Standby Shares") equal to the
Shortfall (as defined below) divided by the subscription price per share. The
"Shortfall" shall be equal to the amount by which $10,000,000 ("Offering Price")
exceeds the aggregate subscription price to be paid by stockholders of the
Company (other than the Purchaser) who subscribe for and purchase shares of
Common Stock offered in the Rights Offering on or before the Expiration Date.

         As compensation to Purchaser for its commitment hereunder, the Company
agrees to pay to Purchaser on September 18, 2002, a Standby Commitment Fee of
$600,000 (the "Standby Commitment

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Fee"), in shares of the Company's Common Stock (the "Standby Commitment Fee
Shares"), with each such share being attributed a value ("Value Per Share")
equal to the average Market Price of the Common Stock for the five Stock
Exchange Business Days preceding the date of this Agreement. "Market Price"
means the daily closing sale price of the Common Stock on a Stock Exchange
Business Day of the American Stock Exchange. "Stock Exchange Business Day" means
any day (other than a Saturday or Sunday) on which the American Stock Exchange
is open for business. The Company also agrees to reimburse the Purchaser $50,000
in cash for its legal fees, which cash payment will also be made on September
18, 2002.

         The Company will notify the Purchaser if the Rights Offering will not
occur, was not approved by the stockholders or was terminated by the Company
(such date of notification, the "Termination Date"), in which event this
Agreement will terminate (except for the applicable provisions of this Section
2, Section 4, and Sections 10 through 16). In such event, Purchaser shall be
entitled to retain one-half of the Standby Commitment Fee Shares. Within thirty
(30) days from the Termination Date, the Purchaser shall either (x) return the
other half of the Standby Commitment Fee Shares to the Company, without payment
therefor by the Company, or (y) retain the other half of the Standby Commitment
Fee Shares and remit to the Company an amount equal to $300,000, to be paid by
the Purchaser by certified or official bank check or by wire transfer and
payable in same day funds to an account or accounts designated by the Company.
The Purchaser may not assign or delegate any of its rights with respect to the
option granted in this Section 2 without the prior written consent of the
Company.

         The Purchaser represents and warrants to the Company that (i) it was
not created for the purpose of acquiring the Common Stock and is an "accredited
investor" (as defined in Rule 501 of Regulation D under Act); (ii) it will be
acquiring the Common Stock for its own account, for investment purposes only,
and not with a view to the resale or distribution thereof, except pursuant to
effective registrations or qualifications relating thereto under the Act and
applicable state securities or blue sky laws or pursuant to an exemption
therefrom; provided, however, that in making such representation, the Purchaser
does not agree to hold the Common Stock for any minimum or specific term and
reserves the right to sell, transfer or otherwise dispose of the Common Stock at
any time in accordance with federal and state securities laws applicable to such
sale, transfer or disposition; (iii) it understands that (A) the Common Stock
has not been registered under the Act or the securities laws of any state or
other jurisdiction in reliance upon exemptions from such registration
requirements for non-public offerings; (B) the shares of Common Stock are
"restricted securities" as defined in Rule 144 under the Act and may not be
sold, pledged or otherwise transferred except pursuant to effective
registrations or qualifications relating thereto under the Act and applicable
state securities or blue sky laws or pursuant to an exemption therefrom; and (C)
the Company has no agreement with the Purchaser to register or qualify the
Common Stock under any state or federal securities laws; and (iv) that an
appropriate restrictive legend will be placed on the certificate or certificates
representing the shares of Common Stock that may be issued pursuant to this
Section 2.

         3. Delivery and Payment. Delivery and payment for the Securities shall
be made at 10:00 A.M., New York City time, on the sixth (6/th/) business day
following the Expiration Date, which date and time may be postponed by agreement
between Purchaser and the Company (such date and time of delivery and payment
for the Securities being herein called the "Closing Date"). Delivery of the
Securities shall be made to Purchaser against payment by Purchaser of the
respective aggregate purchase prices of the Securities being sold by the
Company, by certified or official bank check or by wire transfer and payable in
same day funds to an account or accounts designated in writing by the Company at
least two business days before the Closing Date; provided, however, that the
Purchaser may apply all or a portion of the payment for the Securities to the
principal and interest due and owing on the Closing date on the Company's
promissory notes payable to the Purchaser. Purchaser shall notify the Company of
such application and the amount thereof at least two business days prior to the
Closing date, together with documentation reasonably satisfactory to the Company
verifying the amount of such application. If a note or notes are paid in full,
the Purchaser shall tender the promissory note or notes to the Company for
cancellation. Delivery of the

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Securities shall be made at such location as Purchaser shall reasonably
designate at least one business day in advance of the Closing Date and payment
for such Securities shall be made at such office as the parties may agree upon.
Certificates for the Securities shall be registered in such names and in such
denominations as Purchaser may request not less than forty-eight hours in
advance of the Closing Date.

         4.   No Offering by Purchaser. It is understood that Purchaser does not
intend to offer the Common Stock (including, but not limited to, the Securities)
for sale to the public.

         5.   Agreements.

         (a)  The Company agrees with Purchaser that:

              (i)   The Company will use its best efforts to cause the
         Registration Statement, and any amendments thereof, including any
         post-effective amendment, to become effective as soon as practicable.
         Prior to the termination of the offering of the Rights and the
         Securities, the Company will not file any amendment to the Registration
         Statement or supplement to the Prospectus without Purchaser's prior
         consent, which consent shall not be unreasonably withheld or delayed.
         Subject to the foregoing sentence, if filing of the Prospectus is
         otherwise required under Rule 424(b), the Company will cause the
         Prospectus, properly completed, and any supplement thereto to be filed
         with the Commission pursuant to the applicable paragraph of Rule 424(b)
         within the time period prescribed and will provide evidence
         satisfactory to Purchaser of such timely filing. The Company will
         promptly advise Purchaser (A) when the Registration Statement and any
         amendment thereto, shall have become effective, (B) when the
         Prospectus, and any supplement thereto, shall have been filed (if
         required) with the Commission pursuant to Rule 424(b), (C) when, prior
         to termination of the Rights Offering, any amendment to the
         Registration Statement shall have been filed or become effective, (D)
         of any request by the Commission for any amendment of the Registration
         Statement or supplement to the Prospectus or for any additional
         information, (E) of the issuance by the Commission of any stop order
         suspending the effectiveness of the Registration Statement or the
         institution or threatening of any proceeding for that purpose, (F) of
         the receipt by the Company of any notification with respect to the
         suspension of the qualification of the Securities for sale in any
         jurisdiction or the initiation or threatening of any proceeding for
         such purpose and (G) if any of the representations and warranties
         contained in Section 1 hereof becomes inaccurate in any material
         respect subsequent to the date hereof. The Company will use its best
         efforts to prevent the issuance of any such stop order and, if issued,
         to obtain as soon as possible the withdrawal thereof.

              (ii)  If, at any time when a prospectus relating to the Rights or
         the Securities is required to be delivered under the Act, any event
         occurs as a result of which the Prospectus as then supplemented would
         include any untrue statement of a material fact or omit to state any
         material fact necessary to make the statements therein in the light of
         the circumstances under which they were made not misleading, or if it
         shall be necessary to amend the Registration Statement or supplement
         the Prospectus to comply with the Act or the rules thereunder
         (including to comply with Item 512(c) of Regulation S-K under the Act),
         the Company promptly will prepare and file with the Commission, subject
         to the second sentence of paragraph (a)(i) of this Section 5, an
         amendment or supplement which will correct such statement or omission
         or effect such compliance.

              (iii) The Company will furnish to Purchaser without charge as many
         copies of the Prospectus and any supplement thereto as Purchaser may
         reasonably request. The Company will pay the expenses of printing or
         other production of all documents relating to the Rights Offering.

              (iv)  The Company will arrange for the qualification of the Rights
         for distribution and offering and the Securities for distribution,
         offering and sale under the laws of such domestic

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         jurisdictions as Purchaser may designate, and will maintain such
         qualifications in effect so long as required for the distribution of
         the Rights or the Securities, as the case may be.

              (v)   The Company shall at all times reserve and keep available
         for issue upon the exercise of the Rights such number of authorized but
         unissued shares of Common Stock deliverable upon the exercise of the
         Rights as will be sufficient to permit the exercise in full of all
         Rights issued.

         6.   Conditions to Obligations of Purchaser. The obligations of
Purchaser to purchase the Securities shall be subject to the accuracy of the
representations and warranties on the part of the Company contained herein as of
the Execution Time and the Closing Date, to the accuracy of the statements of
the Company made in any certificates pursuant to the provisions hereof, to the
performance by the Company of their obligations hereunder and to the following
additional conditions:

         (a)  The Registration Statement shall have become effective; if filing
of the Prospectus, or any supplement thereto, is required pursuant to Rule
424(b), the Prospectus, and any such supplement, will be filed in the manner and
within the time period required by Rule 424(b); and no stop order suspending the
effectiveness of the Registration Statement shall have been issued and no
proceedings for that purpose shall have been instituted or threatened.

         (b)  At the Execution Time and at the Closing Date, the Company shall
have furnished to Purchaser certificates of the Company, dated respectively as
of the Execution Time and the Closing Date and signed by any two executive
officers of the Company, to the effect that the signers of such certificates
have carefully examined the Registration Statement, the Prospectus, any
supplements to the Prospectus and this Agreement and that:

              (i)   the representations and warranties of the Company in this
         Agreement are true and correct in all material respects at and as of
         the Execution Time or on and as of the Closing Date, as the case may
         be, with the same effect as if made at the Execution Time or on the
         Closing Date, as the case may be, and the Company has complied with all
         the agreements and satisfied all the conditions on its part to be
         performed or satisfied at or prior to the Execution Time or Closing
         Date, as applicable;

              (ii)  no stop order suspending the effectiveness of the
         Registration Statement has been issued and no proceedings for that
         purpose have been instituted or, to the Company's knowledge,
         threatened; and

              (iii) since the date of the most recent financial statements
         included in the Prospectus (exclusive of any supplement thereto), there
         has been no material adverse change in the condition (financial or
         other), earnings, business, business prospects or properties of the
         Company and its subsidiaries, whether or not arising from transactions
         in the ordinary course of business, except as set forth in or
         contemplated in the Prospectus or the documents incorporated by
         reference therein (exclusive of any supplement thereto).

         (c)  Subsequent to the Execution Time or, if earlier, the date as of
which information is given in the Registration Statement (exclusive of any
amendment thereof) and the Prospectus (exclusive of any supplement thereto),
there shall not have been any change, or any development involving a prospective
change, in or affecting the business (including the results of operations or
management) or properties of the Company and its subsidiaries the effect of
which is, in the reasonable judgment of Purchaser, so material and adverse as to
make it impractical or inadvisable to proceed with the offering or the delivery
of the Securities as contemplated by the Registration Statement (exclusive of
any amendment thereof) and the Prospectus (exclusive of any supplement thereto).

                                       9

<PAGE>

         (d)  The Company shall have commenced mailing the Subscription
Certificates to record holders of the Common Stock promptly following the
authorization and approval of the issuance of the Common Stock which may be
issued pursuant to the Rights Offering and the terms hereof and shall have
completed such mailing expeditiously, and shall have offered the Common Stock
for subscription in accordance with the terms and under the conditions set forth
in the Prospectus. The Company shall have advised Purchaser daily during the
period when the Rights are exercisable of the number of shares of Common Stock
subscribed for, and prior to 12:00 Noon, New York City time, on the business day
following the Expiration Date, shall have advised Purchaser of the number of
shares of Common Stock subscribed for and of the number of Securities.

         (e)  Prior to the Closing Date, the Company shall have furnished to
Purchaser such further information, certificates and documents as Purchaser may
reasonably request.

         If any of the conditions specified in this Section 6 shall not have
been fulfilled in all material respects when and as provided in this Agreement,
or if any of the certificates mentioned above or elsewhere in this Agreement
shall not be in all material respects reasonably satisfactory in form and
substance to Purchaser and its counsel, this Agreement and all obligations of
Purchaser hereunder may be canceled at, or at any time prior to, the Closing
Date by Purchaser. Notice of such cancellation shall be given to the Company in
writing or by telephone or telegraph confirmed in writing.

         7.   Indemnification and Contribution.

         (a)  The Company agrees to indemnify and hold harmless Purchaser, the
directors, officers, partners, employees and agents of Purchaser and each person
who controls Purchaser within the meaning of either the Act or the Exchange Act
against any and all losses, claims, damages or liabilities, joint or several, to
which they or any of them may become subject under the Act, the Exchange Act or
other Federal or state statutory law or regulation, at common law or otherwise,
insofar as such losses, claims, damages or liabilities (or actions in respect
thereof) arise out of or are based upon (i) any untrue statement or alleged
untrue statement of a material fact contained in the registration statement for
the registration of the Rights and the Securities as originally filed or in any
amendment thereof, or in the Prospectus or any of the Offering Materials, or in
any amendment thereof or supplement thereto, or arise out of or are based upon
the omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading or
(ii) the Rights Offering or the engagement of Purchaser pursuant to, and the
performance by Purchaser of the services contemplated by, this Agreement, and
agrees to reimburse each such indemnified party, as incurred, for any reasonable
legal or other expenses reasonably incurred by them in connection with
investigating or defending any such loss, claim, damage, liability or action;
provided, however, that the Company will not be liable in any such case to the
extent that any such loss, claim, damage or liability (A) arises out of or is
based upon any such untrue statement or alleged untrue statement or omission or
alleged omission made therein in reliance upon and in conformity with written
information furnished to the Company by Purchaser specifically for inclusion
therein or (B) in the case of clause (a)(ii) of this Section 7, is the result of
the bad faith, willful misconduct, or negligence of such indemnified party or
any party related to an indemnified party or to have resulted from a breach of
this Agreement or a violation of Regulation M under the Exchange Act by the
indemnified party, other than actions performed at the written request or with
the consent of the Company. This indemnity agreement will be in addition to any
liability which Company may otherwise have.

         The Company also agrees that no indemnified party shall have any
liability (whether direct or indirect, in contract or tort or otherwise) to the
Company or its security holders or creditors related to or arising out of the
engagement of Purchaser pursuant to, or the performance by Purchaser of the
services

                                       10

<PAGE>

contemplated by, this Agreement, except to the extent that any loss, claim,
damage or liability is found in a final judgment by a court to have resulted
from the indemnified party's willful misconduct, bad faith, or negligence or a
breach by Purchaser of its obligations under this Agreement.

         (b) Purchaser agrees to indemnify and hold harmless the Company, each
of its directors, each of its officers who signs the Registration Statement, and
each person who controls the Company within the meaning of the Act or the
Exchange Act, to the same extent as the foregoing indemnity from the Company to
Purchaser, but only with reference to written information relating to Purchaser
furnished to the Company by Purchaser specifically for inclusion in the
documents referred to in the foregoing indemnity. This indemnity agreement will
be in addition to any liability which Purchaser may otherwise have.

         (c) Promptly after receipt by an indemnified party under this Section 7
of notice of the commencement of any action, such indemnified party will, if a
claim in respect thereof is to be made against the indemnifying party under this
Section 7, notify the indemnifying party in writing of the commencement thereof;
but the failure so to notify the indemnifying party (i) will not relieve it from
liability under paragraph (a) or (b) above unless and to the extent it did not
otherwise learn of such action and such failure results in the forfeiture by the
indemnifying party of substantial rights and defenses and (ii) will not, in any
event, relieve the indemnifying party from any obligations to any indemnified
party other than the indemnification obligation provided in paragraph (a) or (b)
above. The indemnifying party shall be entitled to appoint counsel of the
indemnifying party's choice at the indemnifying party's expense to represent the
indemnified party in any action for which indemnification is sought (in which
case the indemnifying party shall not thereafter be responsible for the fees and
expenses of any separate counsel retained by the indemnified party or parties
except as set forth below); provided, however, that such counsel shall be
reasonably satisfactory to the indemnified party. Notwithstanding the
indemnifying party's election to appoint counsel to represent the indemnified
party in an action, the indemnified party shall have the right to employ
separate counsel (including local counsel), and the indemnifying party shall
bear the reasonable fees, costs and expenses of such separate counsel if (i) the
use of counsel chosen by the indemnifying party to represent the indemnified
party would present such counsel with a conflict of interest, (ii) the actual or
potential defendants in, or targets of, any such action include both the
indemnified party and the indemnifying party and the indemnified party shall
have reasonably concluded that there may be legal defenses available to it
and/or other indemnified parties which are different from or additional to those
available to the indemnifying party (it being understood, however, that in
connection with such action the indemnifying party shall not be liable for the
expenses of more than one separate counsel (in addition to local counsel) in any
one action or separate but substantially similar actions in the same
jurisdiction arising out of the same general allegations or circumstances,
representing the indemnified parties who are parties to such action), (iii) the
indemnifying party shall not have employed counsel reasonably satisfactory to
the indemnified party to represent the indemnified party within a reasonable
time after notice of the institution of such action or (iv) the indemnifying
party shall authorize the indemnified party to employ separate counsel at the
expense of the indemnifying party. An indemnifying party will not, without the
prior written consent of the indemnified parties, settle or compromise or
consent to the entry of any judgment with respect to any pending or threatened
claim, action, suit or proceeding in respect of which indemnification or
contribution may be sought hereunder (whether or not the indemnified parties are
actual or potential parties to such claim or action) unless (x) such settlement,
compromise or consent includes an unconditional release of each indemnified
party from all liability arising out of such claim, action, suit or proceeding
or (y) such settlement, compromise or consent involves only the payment of money
damages and no other relief.

         (d) In the event that the indemnity provided in paragraph (a) or (b) of
this Section 7 is unavailable to or insufficient to hold harmless an indemnified
party for any reason, the Company and Purchaser agree to contribute to the
aggregate losses, claims, damages and liabilities (including legal or other
expenses reasonably incurred in connection with investigating or defending same)
(collectively "Losses") to which the Company, on the one hand, and Purchaser, on
the other hand, may be subject in such

                                       11

<PAGE>

proportion as is appropriate to reflect the relative benefits received by the
Company, on the one hand, and by Purchaser, on the other hand, from the purchase
of the Securities; provided, however, that in no case shall Purchaser be
responsible for any amount in excess of the aggregate compensation paid
hereunder to Purchaser in respect of the Securities purchased by Purchaser
hereunder. If the allocation provided by the immediately preceding sentence is
unavailable for any reason, the Company, on the one hand, and Purchaser, on the
other hand, shall contribute in such proportion as is appropriate to reflect not
only such relative benefits but also the relative fault of the Company, on the
one hand, and of Purchaser, on the other hand, in connection with the statements
or omissions which resulted in such Losses as well as any other relevant
equitable considerations. Benefits received by the Company shall be deemed to be
equal to the total net proceeds from the Rights Offering (before deducting
expenses), as set forth on the cover page of the Prospectus (assuming that all
such Rights are exercised), and benefits received by Purchaser shall be deemed
to be equal to the total compensation paid to Purchaser hereunder. Relative
fault shall be determined by reference to whether any alleged untrue statement
or omission relates to information provided by the Company or Purchaser. The
Company and Purchaser agree that it would not be just and equitable if
contribution were determined by pro rata allocation or any other method of
allocation which does not take account of the equitable considerations referred
to above. Notwithstanding the provisions of this paragraph (d), no person guilty
of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act)
shall be entitled to contribution from any person who was not guilty of such
fraudulent misrepresentation. For purposes of this Section 7, each person who
controls Purchaser within the meaning of either the Act or the Exchange Act and
each director, officer, partner, employee and agent of Purchaser shall have the
same rights to contribution as Purchaser, and each person who controls the
Company within the meaning of either the Act or the Exchange Act, each officer
of the Company who shall have signed the Registration Statement and each
director of the Company shall have the same rights to contribution as the
Company, subject in each case to the applicable terms and conditions of this
paragraph (d).

         8.  Termination. This Agreement shall be subject to termination in the
absolute discretion of Purchaser, by notice given to the Company prior to
delivery of and payment for the Securities, if prior to such time trading in the
Company's Common Stock shall have been suspended by the Commission or the
American Stock Exchange or trading in securities generally on such Exchange
shall have been suspended or limited.

         9.  Representations and Indemnities to Survive. The respective
agreements, representations, warranties, indemnities and other statements of the
Company or its officers and of Purchaser set forth in or made pursuant to this
Agreement will remain in full force and effect, regardless of any investigation
made by or on behalf of Purchaser or the Company or any of the officers,
directors or controlling persons referred to in Section 7 hereof, and will
survive delivery of and payment for the Securities. The provisions of the third
paragraph of Section 2 hereof and the provisions of Section 7 hereof shall
survive the termination or cancellation of this Agreement.

         10. Notices. All communications hereunder will be in writing and
effective only on receipt, and, if sent to Purchaser, will be mailed, delivered
or telegraphed and confirmed to it at:

         Lyford Investments Enterprises Ltd.
         720 5/th/ Ave., 9/th/ Floor
         New York, New York 10019
         Attention: Mr. Alan Quasha
         Facsimile: 212-231-3939

or at such other address as Purchaser may hereafter designate by notice to the
Company.

If sent to the Company, will be mailed, delivered or telegraphed and confirmed
to it at:

                                       12

<PAGE>

         Harken Energy Corporation
         580 WestLake Park Boulevard, Suite 600
         Houston, Texas 77079
         Attention: A. Wayne Hennecke
         Facsimile: (281) 504-4104

or at such other address as the Company may hereafter designate by notice to
Purchaser.

         11. Successors. This Agreement will inure to the benefit of and be
binding upon the parties hereto and their respective successors and the officers
and directors and controlling persons referred to in Section 7 hereof, and no
other person will have any right or obligation hereunder. No party to this
Agreement may assign its rights under this Agreement to any other person without
the prior written consent of the other party hereto, except that Purchaser may
assign its rights hereunder to one or more direct or indirect wholly-owned
subsidiaries of Purchaser, provided that Purchaser shall continue to be
obligated to perform all the obligations to be performed by Purchaser hereunder.

         12. Applicable Law. This Agreement will be governed by and construed in
accordance with the laws of the State of Delaware.

         13. Business Day. For purposes of this Agreement, "business day" means
any day on which the American Stock Exchange is open for trading.

         14. Severablity. If any provision of this Agreement is held to be
illegal, invalid or unenforceable under any present or future law, and if the
rights or obligations of any party hereto under this Agreement will not be
materially and adversely affected thereby, (i) such provision will be fully
severable, (ii) this Agreement will be construed and enforced as if such
illegal, invalid or unenforceable provision had never comprised a part hereof,
(iii) the remaining provisions of this Agreement will remain in full force and
effect and will not be affected by the illegal, invalid or unenforceable
provision or by its severance herefrom and (iv) in lieu of such illegal, invalid
or unenforceable provision, there will be added automatically as a part of this
Agreement a legal, valid and enforceable provision as similar in terms to such
illegal, invalid or unenforceable provision as may be possible and mutually
acceptable to the parties herein.

         15. Counterparts. This Agreement may be signed in any number of
counterparts, each of which shall be an original, with the same effect as if the
signatures thereto and hereto were upon the same instrument.

         16. Amendments. This Agreement may only be amended by an instrument in
writing signed by the parties hereto.

                                    * * * * *

                                       13

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed, all as of the day and year first written above.


                                            HARKEN ENERGY CORPORATION


                                            By: /s/ Bruce N. Huff
                                                --------------------------------
                                            Name:  Bruce N. Huff
                                            Title: President


                                            LYFORD INVESTMENTS ENTERPRISES LTD.


                                            By: /s/ Alan G. Quasha
                                                --------------------------------
                                            Name:  Alan G. Quasha
                                            Title: Attorney-in-Fact

                                       14

<PAGE>

                                   SCHEDULE 1

None.

                                       15