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                                                               EXHIBIT (a)(1)(D)

                           Offer to Purchase for Cash

                     All Outstanding Shares of Common Stock

           (Including the Associated Preferred Stock Purchase Rights)
                                       of

                         BARRETT RESOURCES CORPORATION
                                       at

                              $55.00 Net Per Share
                                       by

                            SRM ACQUISITION COMPANY,
                     an indirect wholly owned subsidiary of

                               SHELL OIL COMPANY

    THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK
           CITY TIME, ON APRIL 6, 2001, UNLESS THE OFFER IS EXTENDED.

                                                                  March 12, 2001

To Brokers, Dealers, Commercial Banks,
Trust Companies and Other Nominees:

    We have been appointed by SRM Acquisition Company, a Delaware corporation
(the "Purchaser") and an indirect wholly owned subsidiary of Shell Oil Company,
a Delaware corporation ("Shell"), to act as Dealer Manager in connection with
the Purchaser's offer to purchase (1) all outstanding shares of common stock,
par value $.01 per share (the "shares"), of Barrett Resources Corporation, a
Delaware corporation (the "Company"), and (2) the associated preferred stock
purchase rights (the "Rights") outstanding under the Rights Agreement (the
"Rights Agreement") dated as of August 5, 1997 by and between the Company and
BankBoston, N.A., as Rights Agent, as amended, at $55.00 per share, net to the
seller in cash, upon the terms and subject to the conditions set forth in the
Purchaser's Offer to Purchase dated March 12, 2001 (the "Offer to Purchase"),
and the related Letter of Transmittal (which, together with any supplements or
amendments thereto, collectively constitute the "Offer"). Unless the context
otherwise requires, all references to shares shall be deemed to include the
associated Rights, and all references to the Rights shall be deemed to include
the benefits that may inure to holders of the Rights pursuant to the Rights
Agreement.

    Unless the Rights are redeemed prior to the Expiration Date (as defined in
the Offer to Purchase), holders of shares will be required to tender one
associated Right for each share tendered in order to effect a valid tender of
such share. Accordingly, stockholders who sell their Rights separately from
their shares and do not otherwise acquire Rights may not be able to satisfy the
requirements of the Offer for the tender of shares. If the Distribution Date (as
defined in the Offer to Purchase) has not occurred prior to the Expiration Date,
a tender of shares will also constitute a tender of the associated Rights. If
the Distribution Date has occurred and Rights Certificates (as defined in the
Offer to Purchase) have been distributed to holders of shares prior to the time
a holder's shares are purchased pursuant to the Offer, in order for Rights (and
the corresponding shares) to be validly tendered, Rights Certificates
representing a number of Rights equal to the number of shares tendered must be
delivered to the Depositary (as defined below) or, if available, a Book-Entry
Confirmation (as defined in the Offer to Purchase) must be received by the
Depositary with respect thereto. If the Distribution Date has occurred and
Rights Certificates have not been distributed prior to the time shares are
purchased pursuant to the Offer, Rights may be tendered prior to a stockholder
receiving Rights Certificates by use of the guaranteed delivery procedure
described in Section 2 of the Offer to Purchase. In any case, a tender of shares
constitutes an agreement by the tendering stockholder to deliver Rights
Certificates representing a number of Rights equal to the number of shares
tendered pursuant to the Offer to the Depositary within a period ending on the
later of (1) three trading days after the date of execution of the Notice of
Guaranteed Delivery and (2) three business days after the date Rights
Certificates are
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distributed. A "trading day" is a day on which the New York Stock Exchange is
open for business. The Purchaser reserves the right to require that the
Depositary receive Rights Certificates, or a Book-Entry Confirmation, if
available, with respect to such Rights prior to accepting the related shares for
payment pursuant to the Offer if the Distribution Date has occurred prior to the
Expiration Date.

    If a stockholder desires to tender shares and Rights pursuant to the Offer
and such stockholder's share certificates or, if applicable, Rights
Certificates, are not immediately available (including, if the Distribution Date
has occurred, but Rights Certificates have not yet been distributed) or time
will not permit all required documents to reach the Depositary prior to the
Expiration Date or the procedures for book-entry transfer cannot be completed on
a timely basis, such shares or Rights may nevertheless be tendered according to
the guaranteed delivery procedures set forth in Section 2 of the Offer to
Purchase. See Instruction 2 of the Letter of Transmittal. Delivery of documents
to the Book-Entry Transfer Facility (as defined in the Offer to Purchase) in
accordance with the Book-Entry Transfer Facility's procedures does not
constitute delivery to the Depositary.

    THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, (1) THERE BEING VALIDLY
TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION DATE THAT NUMBER OF SHARES
THAT, TOGETHER WITH ANY SHARES OWNED BY THE PURCHASER, SHELL OR SHELL'S OTHER
DIRECT OR INDIRECT SUBSIDIARIES, WOULD REPRESENT AT LEAST A MAJORITY OF ALL
OUTSTANDING SHARES ON A FULLY DILUTED BASIS ON THE DATE OF PURCHASE, (2) THE
COMPANY'S RIGHTS HAVING BEEN REDEEMED BY THE BOARD OF DIRECTORS OF THE COMPANY,
OR THE PURCHASER BEING SATISFIED, IN ITS SOLE DISCRETION, THAT THE RIGHTS HAVE
BEEN INVALIDATED OR ARE OTHERWISE INAPPLICABLE TO THE OFFER AND THE PROPOSED
MERGER (AS DEFINED IN THE OFFER TO PURCHASE), (3) THE ACQUISITION OF SHARES
PURSUANT TO THE OFFER AND THE PROPOSED MERGER HAVING BEEN APPROVED PURSUANT TO
SECTION 203 OF THE DELAWARE GENERAL CORPORATION LAW ("SECTION 203"), OR THE
PURCHASER BEING SATISFIED, IN ITS SOLE DISCRETION, THAT THE PROVISIONS OF
SECTION 203 ARE OTHERWISE INAPPLICABLE TO THE ACQUISITION OF THE SHARES PURSUANT
TO THE OFFER AND THE PROPOSED MERGER, (4) THE PURCHASER BEING SATISFIED, IN ITS
SOLE DISCRETION, THAT THE PROVISIONS OF ARTICLE IV OF THE COMPANY'S BYLAWS ARE
INAPPLICABLE TO THE ACQUISITION OF SHARES PURSUANT TO THE OFFER AND THE PROPOSED
MERGER AND (5) THE WAITING PERIODS UNDER THE HART-SCOTT-RODINO ANTITRUST
IMPROVEMENTS ACT OF 1976 APPLICABLE TO THE PURCHASE OF SHARES UNDER THE OFFER
HAVING EXPIRED OR BEEN TERMINATED. CERTAIN OTHER CONDITIONS TO THE OFFER ARE
DESCRIBED IN SECTIONS 14 AND 15 OF THE OFFER TO PURCHASE.

    Please furnish copies of the enclosed materials to those of your clients for
whom you hold shares and Rights registered in your name or in the name of your
nominee. Enclosed herewith are copies of the following documents:

        1. The Offer to Purchase dated March 12, 2001;

        2. The Letter of Transmittal to be used by stockholders of the Company
    accepting the Offer;

        3. A printed form of letter that may be sent to your clients for whose
    account you hold shares and Rights in your name or in the name of a nominee,
    with space provided for obtaining such client's instructions with regard to
    the Offer;

        4. The Notice of Guaranteed Delivery;

        5. Guidelines of the Internal Revenue Service for Certification of
    Taxpayer Identification Number on Substitute Form W-9; and

        6. A return envelope addressed to Wilmington Trust Company, the
    Depositary.

    WE URGE YOU TO CONTACT YOUR CLIENTS PROMPTLY.  PLEASE NOTE THAT THE OFFER
AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON
APRIL 6, 2001, UNLESS THE OFFER IS EXTENDED.

    In all cases, payment for shares and Rights accepted for payment pursuant to
the Offer will be made only after timely receipt by Wilmington Trust Company
(the "Depositary") of (a) certificates for (or a timely Book-Entry Confirmation
(as defined in the Offer to Purchase) with respect to) such shares and Rights,
(b) a Letter of Transmittal (or a facsimile thereof), properly completed and
duly executed, with any required signature guarantees, or, in the case of a
book-entry transfer effected pursuant to the procedures described in Section 2
of the Offer to Purchase, an Agent's Message (as defined

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in the Offer to Purchase), and (c) any other documents required by the Letter of
Transmittal. Accordingly, tendering stockholders may be paid at different times
depending upon when certificates for shares or Rights, if applicable, or Book-
Entry Confirmations with respect to shares or, if applicable, Rights are
actually received by the Depositary. THE PURCHASER SHALL NOT HAVE ANY OBLIGATION
TO PAY INTEREST ON THE PURCHASE PRICE FOR TENDERED SHARES, WHETHER OR NOT THE
PURCHASER EXERCISES ITS RIGHT TO EXTEND THE OFFER.

    Neither the Purchaser nor Shell will pay any fees or commissions to any
broker or dealer or other person (other than the Dealer Manager (as defined in
the Offer to Purchase) and the Information Agent (as defined in the Offer to
Purchase) in connection with the solicitation of tenders of shares pursuant to
the Offer. You will be reimbursed upon request for customary mailing and
handling expenses incurred by you in forwarding the enclosed offering materials
to your customers.

    Questions and requests for additional copies of the enclosed material may be
directed to the Information Agent or the Dealer Manager at their respective
addresses and telephone numbers set forth on the back cover of the enclosed
Offer to Purchase.

                                            Very truly yours,

                                            LEHMAN BROTHERS

NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL RENDER YOU OR ANY
OTHER PERSON THE AGENT OF THE PURCHASER, SHELL, THE DEALER MANAGER, THE
DEPOSITARY, THE INFORMATION AGENT OR ANY AFFILIATE THEREOF OR AUTHORIZE YOU OR
ANY OTHER PERSON TO GIVE ANY INFORMATION OR USE ANY DOCUMENT OR MAKE ANY
STATEMENTS ON BEHALF OF ANY OF THEM WITH RESPECT TO THE OFFER OTHER THAN THE
ENCLOSED DOCUMENTS AND THE STATEMENT CONTAINED THEREIN.

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