Summary of Company Net Oil and Gas Proved Reserves⁽¹⁾
As of December 31, 2010
Forecast Prices and Costs

USE OF PROCEEDS

        We estimate that the net proceeds from this offering will be approximately US$                        , after deducting the underwriting commissions and estimated expenses of the offering of approximately US$                        . The net proceeds received by us from the sale of the notes will be used to repay borrowings under our credit facilities. The net proceeds that are not utilized immediately will be invested in short-term marketable securities.

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CONSOLIDATED CAPITALIZATION

        The following table sets forth our consolidated capitalization as at September 30, 2011 on an actual basis and on an adjusted basis to give effect to the issuance and sale of the notes and the application of the net proceeds to be received from the offering as described above in "Use of Proceeds."

        You should read this table together with our audited and unaudited consolidated financial statements, which are incorporated by reference herein. All US$ amounts have been converted to Canadian dollars using the exchange rate of US$0.9626 equals $1.00 at September 30, 2011.

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PRO FORMA INTEREST COVERAGE

        The following pro forma coverage ratios have been prepared in accordance with Canadian securities law requirements and are included in this prospectus supplement in accordance with Canadian disclosure requirements.

        The following pro forma coverage ratios for the twelve month periods ended September 30, 2011 and December 31, 2010 have been calculated based on information contained within our financial statements for the related periods. The following pro forma ratios have been calculated to give effect to the issue of the notes pursuant to this prospectus supplement, and the application of the estimated net proceeds to repay debt as discussed under "Use of Proceeds" as if repayments had occurred at the beginning of the respective periods. The pro forma interest coverage ratios set forth below do not purport to be indicative of the actual interest coverage ratios that would have occurred if each of the foregoing events had actually occurred on the foregoing dates, nor to be indicative of interest coverage ratios for any future periods.

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DESCRIPTION OF THE NOTES

        The following description of the particular terms of the notes supplements, and to the extent inconsistent with replaces, the description of the debt securities set forth under "Description of Debt Securities" in the accompanying prospectus and should be read in conjunction with that description.

General

        The notes will be our direct unsecured obligations and will rank pari passu with all of our other unsubordinated and unsecured indebtedness from time to time outstanding.

        The notes will be structurally subordinated to all existing indebtedness and future liabilities of any of our corporate or partnership subsidiaries, including trade payables and other indebtedness.

        The                        Notes will initially be issued in an aggregate principal amount of US$                        and will mature on                                    . The                        Notes will bear interest at the rate of            % per year from                                    , 2011, or from the most recent date to which interest has been paid or provided for, payable semi-annually on                                     and                                    of each year, commencing                                    , 2012, to the persons in whose names the                        Notes are registered at the close of business on the preceding                                    or                                     , respectively.

        The                        Notes will initially be issued in an aggregate principal amount of US$                        and will mature on                                    . The                        Notes will bear interest at the rate of            % per year from                                    , 2011, or from the most recent date to which interest has been paid or provided for, payable semi-annually on                                     and                                    of each year, commencing                                    , 2012, to the persons in whose names the                        Notes are registered at the close of business on the preceding                                    or                                     , respectively.

        We may from time to time without notice to, or the consent of, the holders of the notes, create and issue additional                        Notes or                        Notes under the Indenture. Such additional                        Notes and                        Notes will have the same terms as the                        Notes or                        Notes, as the case may be, offered hereby in all respects (or in all respects except for the payment of interest accruing prior to the issue date of the additional                        Notes and                        Notes or except for the first payments of interest following the issue date of the additional                        Notes and                        Notes) so that the additional                        Notes or                        Notes may be consolidated and form a single series with the                        Notes or                        Notes, as the case may be. In the event that additional                        Notes or                        Notes are issued, we will prepare a new prospectus supplement.

        For a discussion of the ranking of the notes and the indebtedness and other liabilities of our subsidiaries, see "Description of Debt Securities—Ranking and Other Indebtedness" in the accompanying prospectus.

        Payment on the principal, premium, if any, and interest will be made in United States dollars. The notes will not be entitled to the benefits of any sinking fund.

        The provisions of the Indenture relating to the payment of Additional Amounts in respect of Canadian withholding taxes in certain circumstances (described under the caption "Description of Debt Securities—Additional Amounts" in the accompanying prospectus) and the provisions of the Indenture relating to the redemption of notes in the event of specified changes in Canadian withholding tax law on or after the date of this prospectus supplement (described under the caption "Description of Debt Securities—Tax Redemption" in the accompanying prospectus) will apply to the notes.

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        The notes will be issued in minimum denominations of US$2,000 and integral multiples of US$1,000 in excess thereof.

Optional Redemption

        We may redeem the                        Notes and, prior to                        , we may redeem the                        Notes, in each case, in whole or in part, at our option at any time or from time to time at a redemption price equal to the greater of: (1) 100% of the principal amount of the notes of the applicable series, or (2) the sum of the present values of the remaining scheduled payments of principal and interest thereon (exclusive of any portion of the payments of interest accrued to the date of redemption) discounted to the redemption date on a semi-annual basis at the Treasury Yield plus            basis points, in the case of the                                    Notes and plus            basis points, in the case of the                                    Notes, in each case, together with accrued interest to the date of redemption. Interest will be calculated on the basis of a 360-day year consisting of twelve 30-day months.

        On or after                        , we may redeem the                        Notes, in whole or in part, at a redemption price equal to 100% of the principal amount of the                        Notes to be redeemed, plus accrued and unpaid interest thereon to the date of redemption.

        Holders of notes to be redeemed will receive notice of redemption by first-class mail at least 30 and not more than 60 days prior to the date fixed for redemption.

        Unless we default in the payment of the redemption price, on or after the redemption date, interest will cease to accrue on the notes of the applicable series or the portions of such notes called for redemption.

        "Comparable Treasury Issue" means the United States Treasury security or securities selected by an Independent Investment Banker as having an actual or interpolated maturity comparable to the remaining term of the notes to be redeemed that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of the notes.

        "Comparable Treasury Price" means (A) the average of the Reference Treasury Dealer Quotations for such redemption date, after excluding the highest and lowest of such Reference Treasury Dealer Quotations, or (B) if the Trustee obtains fewer than four such Reference Treasury Dealer Quotations, the average of all such Quotations.

        "Independent Investment Banker" means one of the Reference Treasury Dealers selected by the Trustee after consultation with us or, if such firm is unwilling or unable to select the Comparable Treasury Issue, an independent investment banking institution of national standing in the United States appointed by the Trustee after consultation with us.

        "Reference Treasury Dealer" means (A) J.P. Morgan Securities LLC, BNP Paribas Securities Corp. and RBC Capital Markets, LLC, or their respective successors; provided, however, that if any shall cease to be a primary U.S. Government securities dealer in The City of New York (a "Primary Treasury Dealer"), we will substitute another Primary Treasury Dealer, and (B) any other Primary Treasury Dealer selected by the Trustee after consultation with us.

        "Reference Treasury Dealer Quotations" means, with respect to each Reference Treasury Dealer and any redemption date, the average, as determined by the Trustee, of the bid and ask prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Trustee by such Reference Treasury Dealer at 3:30 p.m. New York time on the third business day preceding such redemption date.

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        "Treasury Yield" means, with respect to any redemption date, the rate per annum equal to the semi-annual equivalent yield to maturity or interpolated (on a day count basis) of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for that redemption date.

Book-Entry System

        The Depository Trust Company (the "Depository") will act as securities depository for the notes. The notes will be represented by one or more registered global notes (collectively, the "Registered Global Securities") registered in the name of Cede & Co. (the Depository's partnership nominee) or such other name as may be requested by an authorized representative of the Depository. The provisions set forth under "Description of Debt Securities—Registered Global Securities" in the accompanying prospectus will be applicable to the notes. Accordingly, beneficial interests in the notes will be shown on, and transfers of the notes will be effected, only through, records maintained by the Depository and its Direct and Indirect Participants (defined below). Except as described under "Description of Debt Securities—Registered Global Securities" in the accompanying prospectus, owners of beneficial interests in the Registered Global Securities representing the notes will not be entitled to receive notes in definitive form and will not be considered Holders of notes under the Indenture.

        The following is based on information furnished by the Depositary:

        The Depository is a limited-purpose trust company organized under the New York Banking Law, a "banking organization" within the meaning of the New York Banking Law, a member of the Federal Reserve System, a "clearing corporation" within the meaning of the New York Uniform Commercial Code and a "clearing agency" registered pursuant to the provisions of Section 17A of the U.S. Securities Exchange Act of 1934. The Depository holds securities that its participants ("Direct Participants") deposit with the Depository. The Depository also facilitates the settlement among Direct Participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerized book-entry changes in Direct Participants' accounts, thereby eliminating the need for physical movement of securities certificates. Direct Participants include: securities brokers and dealers, banks, trust companies, clearing corporations, and certain other organizations.

        The Depository is a wholly-owned subsidiary of the Depository Trust & Clearing Corporation ("DTCC"). DTCC, in turn, is owned by a number of its Direct Participants and Members of the National Securities Clearing Corporation, Government Securities Clearing Corporation, MBS Clearing Corporation and Emerging Markets Clearing Corporation and by the New York Stock Exchange, Inc., NYSE Amex LLC and the Financial Industry Regulatory Authority, Inc. Access to the Depository's system is also available to others, such as securities brokers and dealers, banks, trust companies and clearing corporations that clear through or maintain a custodial relationship with a Direct Participant, either directly or indirectly ("Indirect Participants"). The rules applicable to the Depository and Direct and Indirect Participants are on file with the SEC. All interests in the Registered Global Securities, including those held through the Euroclear System ("Euroclear") or Clearstream Banking, S.A. ("Clearstream"), may be subject to the procedures and requirements of the DTC. Those interests held through Euroclear or Clearstream may also be subject to the procedures and requirements of such systems.

        Purchases of notes under the Depository's system must be made by or through Direct Participants, which will receive a credit for such notes on the Depository's records. The ownership interest of each actual purchaser of notes represented by the Registered Global Securities ("Beneficial Owner") is in turn to be recorded on the Direct and Indirect Participants' records. Beneficial Owners will not receive written confirmation from the Depository of their purchase, but Beneficial Owners are expected to receive written confirmations providing details of the transactions, as well as periodic statements of their holdings, from the Direct or Indirect Participants through which such Beneficial Owners entered

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into the transaction. Transfers of ownership interests in the Registered Global Securities representing the notes are to be accomplished by entries made on the books of participants acting on behalf of Beneficial Owners. Beneficial Owners will not receive certificates representing their ownership interests in the Registered Global Securities representing the notes, except in the event that use of the book-entry system for the notes is discontinued or upon the occurrence of certain other events described in the accompanying prospectus.

        To facilitate subsequent transfers, the Registered Global Securities, representing the notes that are deposited by Direct Participants with the Depository, are registered in the name of the Depository's partnership nominee, Cede & Co. or such other name as may be requested by an authorized representative of the Depository. The deposit of the Registered Global Securities with the Depository and its registration in the name of Cede & Co. or such other nominee does not effect any change in beneficial ownership. The Depository has no knowledge of the actual Beneficial Owners of the Registered Global Securities representing the notes; the Depository's records reflect only the identity of the Direct Participants to whose accounts such notes are credited, which may or may not be the Beneficial Owners. The Direct or Indirect Participants will remain responsible for keeping account of their holdings on behalf of their customers.

        Conveyance of notices and other communications by the Depository to Direct Participants, by Direct Participants to Indirect Participants, and by Direct Participants and Indirect Participants to Beneficial Owners will be governed by arrangements among them, subject to any statutory or regulatory requirements as may be in effect from time to time.

        Neither the Depository nor Cede & Co. (nor any other Depository nominee) will consent or vote with respect to the Registered Global Securities representing the notes. Under its usual procedures, the Depository mails an omnibus proxy (an "Omnibus Proxy") to us as soon as possible after the record date. The Omnibus Proxy assigns Cede & Co.'s consenting or voting rights to those Direct Participants to whose accounts the notes are credited on the record date (identified in a listing attached to the Omnibus Proxy).

        Principal, premium, if any, and interest payments on the Registered Global Securities representing the notes will be made to Cede & Co., or such nominee as may be requested by an authorized representative of the Depository. The Depository's practice is to credit Direct Participants' accounts on the applicable payment date in accordance with their respective holdings shown on the Depository's records, upon the Depository's receipt of funds and corresponding detail information from us or the Trustee on the payment date. Payments by Direct and Indirect Participants to Beneficial Owners will be governed by standing instructions and customary practices, as is the case with securities held for the accounts of customers in bearer form or registered in "street name," and will be the responsibility of such Direct and Indirect Participants and not of the Depository, the Trustee, or us, subject to any statutory or regulatory requirements as may be in effect from time to time. Payment of principal, premium and interest to Cede & Co. (or such other nominee as may be requested by an authorized representative of the Depository) is our responsibility or the responsibility of the Trustee. Disbursement of such payments to Direct Participants is the responsibility of the Depository, and disbursement of such payments to the Beneficial Owners is the responsibility of the Direct and Indirect Participants. Neither we nor the Trustee will have any responsibility or liability for the disbursements of payments in respect of ownership interests in the notes by the Depository or the Direct or Indirect Participants or for maintaining or reviewing any records of the Depository or the Direct or Indirect Participants relating to ownership interests in the notes or the disbursement of payments in respect of the notes.

        The Depository may discontinue providing its services as securities depository with respect to the notes at any time by giving reasonable notice to us or the Trustee. Under such circumstances, in the event that a successor securities depository is not obtained, notes in definitive form are required to be printed and delivered to each Holder.

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        We may decide to discontinue use of the system of book-entry transfers through the Depository (or a successor securities depository). In that event, notes in definitive form will be printed and delivered.

        The information in this section concerning the Depository and the Depository's system has been obtained from sources that we believe to be reliable, but is subject to any changes to the arrangements between us and the Depository and any changes to these procedures that may be instituted unilaterally by the Depository.

Global Clearance and Settlement Procedures

        Initial settlement for the notes will be made in immediately available funds. Secondary market trading between DTC Participants will occur in the ordinary way in accordance with DTC rules and will be settled in immediately available funds using DTC's Same-Day Funds Settlement System. Secondary market trading between Clearstream Participants and/or Euroclear Participants will occur in the ordinary way in accordance with the applicable rules and operating procedures of Clearstream, Luxembourg and the Euroclear System, as applicable.

        Cross-market transfers between persons holding directly or indirectly through DTC on the one hand, and directly or indirectly through Clearstream Participants or Euroclear Participants, on the other, will be effected through DTC in accordance with DTC rules on behalf of the relevant European international clearing system by its U.S. depositary; however, such cross-market transactions will require delivery of instructions to the relevant European international clearing system by the counterparty in such system in accordance with its rules and procedures and within its established deadlines (European time). The relevant European international clearing system will, if the transaction meets its settlement requirements, deliver instructions to its U.S. depositary to take action to effect final settlement on its behalf by delivering or receiving securities in DTC, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to DTC. Clearstream Participants and Euroclear Participants may not deliver instructions directly to their respective U.S. depositaries.

        Because of time-zone differences, credits of notes received in Clearstream, Luxembourg or the Euroclear System as a result of a transaction with a DTC Participant will be made during subsequent securities settlement processing and dated the business day following the DTC settlement date. The credits or any transactions in the notes settled during the processing will be reported to the relevant Euroclear Participant or Clearstream Participant on that business day. Cash received in Clearstream, Luxembourg or the Euroclear System as a result of sales of the notes by or through a Clearstream Participant or a Euroclear Participant to a DTC Participant will be received with value on the DTC settlement date but will be available in the relevant Clearstream, Luxembourg or the Euroclear System cash account only as of the business day following settlement in DTC.

        Although DTC, Clearstream, Luxembourg and the Euroclear System have agreed to the foregoing procedures in order to facilitate transfers of notes among participants of DTC, Clearstream, Luxembourg and the Euroclear System, they are under no obligation to perform or continue to perform such procedures and such procedures may be discontinued or changed at any time.

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CERTAIN INCOME TAX INFORMATION

        The following summary is of a general nature only and is not intended to be, and should not be construed to be, legal or tax advice to any prospective investor and no representation with respect to the tax consequences to any particular investor is made. Accordingly, prospective investors should consult with their own tax advisors for advice with respect to the income tax consequences to them of purchasing, holding or disposing of the notes having regard to their own particular circumstances, including any consequences of an investment in the notes arising under state, provincial or local tax laws in the United States or Canada or tax laws of jurisdictions outside the United States or Canada.

Certain Canadian Federal Income Tax Considerations

        In the opinion of Parlee McLaws LLP, our Canadian counsel, the following is, as of the date hereof, a fair and adequate summary of the principal Canadian federal income tax consequences generally applicable to a purchaser who acquires notes, as beneficial owner, and who, at all relevant times, for purposes of the Income Tax Act (Canada) (the "Tax Act") and any applicable income tax treaty or convention (i) is neither a resident of Canada nor deemed to be a resident of Canada; (ii) deals at arm's length with Canadian Natural, any successor to Canadian Natural, and with any transferees resident or deemed to be resident in Canada to whom the purchaser disposes of notes; (iii) does not use or hold, and is not deemed to use or hold, notes in connection with a trade or business carried on, or deemed to be carried on, in Canada, and (iv) is not an insurer carrying on an insurance business in Canada and elsewhere.

        This summary is based on the current provisions of the Tax Act and the regulations thereunder, counsel's understanding of the current published administrative practices of the Canada Revenue Agency (the "CRA"), and all specific proposals ("Proposals") to amend the Tax Act and the regulations announced by the Minister of Finance (Canada) prior to the date hereof. This summary does not otherwise take into account or anticipate changes in the law or in the administrative practices of the CRA, whether by judicial, governmental or legislative decision or action, nor does it take into account tax legislation or considerations of any province or territory of Canada or any jurisdiction outside Canada. This summary is not exhaustive of all possible Canadian federal income tax consequences and no assurance can be given that any Proposals to amend the Tax Act and the regulations will be enacted as proposed or at all.

        Under the Tax Act, interest, premium, if any, or principal on the notes paid or credited, or deemed to be paid or credited by Canadian Natural to a purchaser will be exempt from Canadian non-resident withholding tax. There are no other Canadian federal taxes on income or capital gains payable under the Tax Act by a purchaser in respect of the acquisition, holding, redemption or disposition of the notes, or the receipt of interest, premium, if any, or principal thereon solely as a consequence of the acquisition, holding, redemption or disposition of the notes.

CERTAIN UNITED STATES FEDERAL INCOME TAX CONSIDERATIONS

        The following is a discussion of certain material U.S. federal income tax consequences of the acquisition, ownership and disposition of the notes by a U.S. Holder, as defined below, that acquires the notes in this initial offering at the price set forth on the cover page. This discussion is not a complete analysis or description of all of the possible tax consequences of such transactions and does not address all tax considerations that might be relevant to particular holders in light of their personal circumstances or to persons that are subject to special tax rules. In particular, the information set forth below deals only with holders that will hold the notes as capital assets for U.S. federal income tax purposes (generally, property held for investment). In addition, this discussion of certain material U.S. federal income tax consequences does not address the tax treatment of special classes of holders, such as financial institutions, regulated investment companies, real estate investment trusts, partnerships

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or other pass-through entities (or investors in such entities), tax-exempt entities, insurance companies, persons holding the notes as part of a hedging, integrated or conversion transaction, constructive sale or "straddle," U.S. expatriates, persons subject to the alternative minimum tax, and dealers or traders in securities or currencies.

        This summary does not address U.S. federal estate and gift tax consequences or tax consequences under any state, local or foreign laws.

        The following discussion is based upon the Internal Revenue Code of 1986, as amended (the "Code"), the Treasury regulations promulgated under the Code, U.S. judicial decisions and administrative pronouncements. All of the preceding authorities are subject to change, possibly with retroactive effect, which may result in U.S. federal income tax consequences different from those discussed below. We have not requested, and will not request, a ruling from the U.S. Internal Revenue Service (the "IRS") with respect to any of the U.S. federal income tax consequences described below. As a result, there can be no assurance that the IRS or a court considering these issues will not disagree with or challenge any of the conclusions we have reached and describe herein.

        For purposes of this discussion, a "U.S. Holder" is a beneficial owner of notes that is (1) an individual who is a citizen or a resident alien of the United States as determined for U.S. federal income tax purposes, (2) a corporation (or other entity treated as a corporation for U.S. federal income tax purposes) created or organized in or under the laws of the United States, any state thereof, or the District of Columbia, (3) an estate the income of which is subject to U.S. federal income taxation regardless of its source, or (4) a trust (A) if a court within the United States is able to exercise primary supervision over its administration and one or more U.S. persons have authority to control all substantial decisions of the trust, or (B) that has a valid election in effect under applicable Treasury regulations to be treated as a U.S. person.

        If a partnership or other pass-through entity holds the notes, the tax treatment of a partner in or owner of the partnership or pass-through entity will generally depend upon the status of the partner or owner and the activities of the entity. If you are a partner in or owner of a partnership or other pass-through entity that is considering holding notes, you should consult your tax advisor regarding the tax consequences of acquiring, owning and disposing of notes.

        The following discussion is for general information only and is not intended to be, nor should it be construed to be, legal or tax advice to any holder or prospective holder of notes, and no opinion or representation with respect to the U.S. federal income tax consequences to any such holder or prospective holder is given.

        We urge holders to consult their own tax advisor regarding the application of U.S. federal, state and local tax laws, as well as any applicable foreign tax laws, to their particular situation.

Payments of Interest

        Each payment of interest on a note will be taxable as ordinary interest income at the time it accrues or is received, in accordance with your method of accounting for U.S. federal income tax purposes. Interest paid on the notes will be income from sources outside the United States for purposes of computing the foreign tax credit allowable to a U.S. Holder. Interest income on a note generally will be considered either "passive category income" or "general category income" for U.S. foreign tax credit purposes. The rules governing the foreign tax credit are complex, and you should consult your tax advisor regarding the availability of the credit under your particular circumstances.

Original Issue Discount

        A note with a term that exceeds one year will be treated as issued with original issue discount ("OID") if the "stated redemption price at maturity" of the note exceeds its "issue price" by at least

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the de minimis amount of ¹/4 of 1 percent of the "stated redemption price at maturity" multiplied by the number of complete years from the issue date of the note to its maturity. A note's "issue price" generally is the first price at which a substantial amount of notes included in the issue of which the note is a part is sold to persons other than bond houses, brokers or similar persons or organizations acting in the capacity of underwriters, placement agents or wholesalers. The "stated redemption price at maturity" of a note is the total of all payments provided by the note that are not payments of "qualified stated interest." Generally, an interest payment on a note is "qualified stated interest" if it is one of a series of stated interest payments on a note that are unconditionally payable at least annually at a single fixed rate.

        It is not expected that the notes will be issued with OID. If, however, the stated redemption price of a note exceeds its issue price by at least the de minimis amount, you will be required to treat such excess amount as OID, which is treated for U.S. federal income tax purposes as accruing over the term of the note as interest income to you. Your adjusted tax basis in a note would be increased by the amount of any OID included in your gross income. In compliance with Treasury regulations, if we determine that the notes have OID, we will provide certain information to the IRS and/or you that is relevant to determining the amount of OID in each accrual period.

Sale, Exchange or Retirement of the Notes

        Upon the sale, exchange, retirement or other disposition of a note, you will generally recognize capital gain or loss in an amount equal to the difference between (i) the amount of cash plus the fair market value of any property received (other than any amount received that is attributable to accrued but unpaid interest not previously included in income, which will be taxable as ordinary interest income) and (ii) your adjusted tax basis in the note at the time of sale, exchange, retirement or other disposition. Your adjusted tax basis in a note generally will be the amount that you paid for the note.

        Any capital gain or loss will be long-term capital gain or loss if at the time of the sale, exchange, retirement or other taxable disposition of the note, the U.S. Holder has held the note for more than one year. Long-term capital gain of non-corporate U.S. Holders, including individual U.S. Holders, is generally taxed at reduced rates. The gain or loss will generally be treated as U.S. source gain or loss. The deductibility of capital losses is subject to limitations.

Additional Tax on Passive Income

        Certain U.S. Holders who are individuals, estates or trusts will be required to pay a 3.8 percent tax on, among other things, interest income and capital gains from the sale or other disposition of notes for taxable years beginning after December 31, 2012.

Information Reporting and Backup Withholding

        In general, information reporting requirements apply to certain payments to U.S. Holders of principal of, and interest on, a note, and the receipt of proceeds on the sale or other disposition (including a retirement or redemption) of a note before maturity, in each case when made within the United States or through certain U.S. intermediaries. In addition, such payments will be subject to backup withholding if a U.S. Holder fails to furnish its taxpayer identification number, fails to certify that such number is correct, fails to certify that such U.S. Holder is not subject to backup withholding, or otherwise fails to comply with the applicable requirements of the backup withholding rules.

        Certain U.S. Holders, including corporations, are generally not subject to backup withholding and information reporting requirements provided their exemption from backup withholding and information reporting are properly established. Backup withholding is not an additional tax. Any amounts withheld from a payment to you will be allowed as a credit against your U.S. federal income tax liability and may entitle you to a refund, provided the required information is furnished to the IRS in a timely

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manner. You should consult your tax advisor regarding the application of backup withholding, the availability of an exemption from backup withholding and the procedure for obtaining such an exemption, if available.

        Certain U.S. Holders who are individuals are required to report information relating to an interest in notes, subject to certain exceptions (including an exception for notes held in accounts maintained by domestic financial institutions). You are urged to consult your tax advisor regarding your reporting requirements.

The EU Savings Directive

        Under the EU Savings Directive, each Member State is required to provide to the tax or other relevant authorities of another Member State details of payments of interest (or other similar income) made by a person within its jurisdiction to, or for the benefit of, an individual resident in that other Member State or to certain limited types of entities established in that other Member State. However, for a transitional period, Austria and Luxembourg are instead required (unless during that period they elect otherwise) to operate a withholding system in relation to such payments (the ending of such transitional period being dependent upon the conclusion of certain other agreements relating to information exchange with certain other countries). The rate of such withholding is currently 35%. A number of non-EU countries and territories have adopted or agreed to adopt similar measures (either provision of information or transitional withholding).

        On September 15, 2008 the European Commission issued a report to the Council of the European Union on the operation of the EU Savings Directive, which included the Commission's advice on the need for changes to the EU Savings Directive. On November 13, 2008, the European Commission published a more detailed proposal for amendments to the EU Savings Directive, which included a number of suggested changes. The European Parliament approved an amended version of this proposal on April 24, 2009 and discussions are currently ongoing at the European Council level. If any of those proposed changes are made in relation to the EU Savings Directive, they may amend or broaden the scope of the requirements described above.

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TRADING PRICE AND VOLUME

        Our common shares are listed for trading on the Toronto Stock Exchange and the New York Stock Exchange under the trading symbol "CNQ".

        The following table outlines the share price trading range and volume of shares traded by month on the Toronto Stock Exchange for the period October 2010 to November 9, 2011:

UNDERWRITING

        We intend to offer the Notes through underwriters. J.P. Morgan Securities LLC, BNP Paribas Securities Corp. and RBC Capital Markets, LLC are acting as joint book-running managers and representatives of the underwriters named below.

        Subject to the terms and conditions stated in the underwriting agreement between us and the underwriters, each underwriter named below has agreed to purchase, and we have agreed to sell to that underwriter, the principal amounts of notes set forth opposite the underwriter's name.

        The underwriting agreement provides that the obligations of the underwriters to purchase the notes included in this offering are subject to approval of legal matters by counsel and to other conditions. The underwriters are obligated to purchase all of the notes of any series if they purchase any of the notes.

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        The underwriters propose to offer some of the notes of each series directly to the public at the applicable public offering price set forth on the cover page of this prospectus supplement and some of the notes of such series to dealers at the public offering price less a concession not to exceed        % and        % of the principal amount of the              Notes and             Notes, respectively. The underwriters may allow, and dealers may reallow a concession not to exceed        % and        % of the principal amount of the             Notes and             Notes, respectively, on sales to other dealers. After the initial offering of the notes to the public, the representatives may change the public offering prices, concessions, and other selling terms. The underwriters may offer to sell the Notes through certain of their affiliates.

        The following table shows the underwriting commissions that we are to pay to the underwriters in connection with this offering (expressed as a percentage of the principal amount of the applicable series of notes).

        In connection with this offering, J.P. Morgan Securities LLC, BNP Paribas Securities Corp. and RBC Capital Markets, LLC, on behalf of the underwriters, may purchase and sell notes in the open market. These transactions may include over-allotment, syndicate covering transactions and stabilizing transactions. Over-allotment involves syndicate sales of the notes in excess of the principal amounts of the notes to be purchased by the underwriters in this offering, which creates a syndicate short position. Syndicate covering transactions involve purchases of the notes in the open market after the distribution has been completed in order to cover syndicate short positions. Stabilizing transactions consist of certain bids or purchases of the notes made for the purpose of preventing or retarding a decline in the market prices of the notes while the offering is in progress.

        The underwriters also may impose a penalty bid. Penalty bids permit the underwriters to reclaim a selling concession from a syndicate member when J.P. Morgan Securities LLC, BNP Paribas Securities Corp. and RBC Capital Markets, LLC, in covering syndicate short positions or making stabilizing purchases, repurchase notes originally sold by that syndicate member.

        Any of these activities may have the effect of preventing or retarding a decline in the market price of the notes. They may also cause the prices of the notes to be higher than the price that otherwise would exist in the open market in the absence of these transactions. The underwriters may conduct these transactions in the over-the-counter market or otherwise. If the underwriters commence any of these transactions, they may discontinue them at any time.

        We have agreed not to offer, sell, contract to sell, pledge, or otherwise dispose of any debt securities, or enter into any related transaction, until the closing of this offering; provided that we may offer and sell Canadian dollar denominated debt securities outside of the United States pursuant to an "MTN program" under National Instrument 44-102 of the Canadian Securities Administrators.

        We estimate that our total expenses for this offering will be US$                (not including the underwriting commissions).

        Some of the underwriters and their affiliates have engaged in, and may in the future engage in, investment banking and other commercial dealings in the ordinary course of business with us or our affiliates. They have received, or may in the future receive, customary fees and commissions for these transactions.

        Each of J.P. Morgan Securities LLC, BNP Paribas Securities Corp. and RBC Capital Markets, LLC is an affiliate of a bank that is currently a lender to us (such affiliates, the "Lenders"), and Canadian

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Natural may be considered to be a connected issuer to each of the Lenders. We were indebted to the Lenders for approximately $657 million as of September 30, 2011 under various credit facilities, representing approximately 7% of our total indebtedness as of that date. At the date hereof these credit facilities are unsecured. We are in compliance with the terms of such credit facilities and the Lenders have not waived any material breach of the agreements governing such credit facilities since their execution on June 15, 2007 and June 24, 2011. Our financial position has not changed materially since the indebtedness under the credit facilities was incurred. Although the net proceeds of this offering will be used to repay borrowings under our credit facilities, none of the proceeds of this offering will be applied to permanently reduce such facilities. None of the banks affiliated with the underwriters referred to above were involved in the decision to offer the notes or in the determination of the terms of the distribution of the notes.

        We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act of 1933, as amended, or to contribute to payments the underwriters may be required to make because of any of those liabilities. The notes will not be qualified for sale under the securities laws of Canada or any province or territory of Canada (other than the Province of Alberta) and may not be, directly or indirectly, offered, sold or delivered in Canada or to residents of Canada in contravention of the securities laws of any province or territory of Canada. Each underwriter has agreed that it will not, directly or indirectly, offer, sell or deliver any notes purchased by it in Canada or to residents of Canada in contravention of the securities laws of any province or territory of Canada.

Conflicts of Interest

        Affiliates of certain of the underwriters are lenders under our credit facilities. Because net proceeds from the offering of the notes will be used to repay indebtedness under our credit facilities, we expect that more than five percent of the net proceeds, not including underwriting compensation, will be directed to one or more of the underwriters or their affiliates, which would be considered a conflict of interest under Financial Industry Regulatory Authority, Inc. ("FINRA") Rule 5121. As such, this offering will be conducted in accordance with FINRA Rule 5121. In accordance with that rule, no "qualified independent underwriter" is required, because the notes are investment grade rated, as that term is defined in the rule. To comply with FINRA Rule 5121, J.P. Morgan Securities LLC, BNP Paribas Securities Corp. and RBC Capital Markets, LLC will not confirm sales to any account over which J.P. Morgan Securities LLC, BNP Paribas Securities Corp. and RBC Capital Markets, LLC, as applicable, exercises discretionary authority without the specific written approval of the accountholder.

Notice to Prospective Investors in the European Economic Area

        In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a "Relevant Member State"), each initial purchaser has represented and agreed that, with effect from and including the date on which the Prospectus Directive is implemented in that Relevant Member State (the "Relevant Implementation Date"), it has not made and will not make an offer of notes to the public in that Relevant Member State prior to the publication of a prospectus in relation to the notes which has been approved by the competent authority in that Relevant Member State or, where appropriate, approved in another Relevant Member State and notified to the competent authority in that Relevant Member State, all in accordance with the Prospectus Directive, except that it may, with effect from and including the Relevant Implementation Date, make an offer of notes to the public in that Relevant Member State at any time the following exemptions are met:

(a)

at any time to any legal entity which is a qualified investor as defined in the Prospective Directive;

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(b)

to fewer than 100, or if the Relevant Member State has implemented the relevant provision of the 2010 PD Amending Directive, 150 natural or legal persons (other than qualified investors as defined in the Prospectus Directive) subject to obtaining the prior consent of the underwriters for any such offer; or



(c)

at any time in any other circumstances falling within Article 3(2) of the Prospectus Directive, provided that no such offer of Notes referred to in (a) to (c) above shall require us or the underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive or supplement a prospectus pursuant to Article 16 of the Prospectus Directive.

        Each person who receives any communication in respect of or purchaser of notes described in this prospectus supplement located within a Relevant Member State will be deemed to have represented, acknowledged and agreed that it is a "qualified investor" within the meaning of Article 2(1)(e) of the Prospectus Directive.

        For the purposes of this provision, the expression an "offer of notes to the public" in relation to any notes in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and the notes to be offered so as to enable an investor to decide to purchase or to subscribe the notes, as the same may be varied in that Relevant Member State by any measure implementing the Prospectus Directive in that Relevant Member State and the expression "Prospectus Directive" means Directive 2003/71/EC and amendments thereto including the 2010 PD Amending Directive, to the extent implemented in the Relevant Member State, and includes any relevant implementing measure in each Relevant Member State. "2010 PD Amending Directive" means Directive 2010/73/FU.

        We have not authorized and do not authorize the making of any offer of the notes through any financial intermediary on our behalf, other than offers made by the underwriters with a view to the final placement of the notes as contemplated in this prospectus supplement. Accordingly, no purchaser of the notes, other than the underwriters, is authorized to make any further offer of the notes on our behalf or on behalf of the underwriters.

Notice to Prospective Investors in the United Kingdom

        Each underwriter has represented and agreed that:

(a)

it has only communicated or caused to be communicated and will only communicate or cause to be communicated an invitation or inducement to engage in investment activity (within the meaning of Section 21 of the Financial Services and Markets Act 2000 of the United Kingdom (the "FSMA")) received by it in connection with the issue or sale of such notes in circumstances in which Section 21(1) of the FSMA does not apply to us; and

(b)

it has complied and will comply with all applicable provisions of the FSMA with respect to anything done by it in relation to the notes in, from or otherwise involving the United Kingdom.

LEGAL MATTERS

        The validity of the notes will be passed upon for us by Parlee McLaws LLP, Calgary, Alberta, and by Paul, Weiss, Rifkind, Wharton & Garrison LLP, New York, New York. The underwriters will be represented with respect to certain United States legal matters by Shearman & Sterling LLP, Toronto, Ontario and New York, New York. As to all matters of Canadian federal and Alberta law, Paul, Weiss, Rifkind, Wharton & Garrison LLP may rely upon the opinion of Parlee McLaws LLP. As to all matters of U.S. federal and New York law, Parlee McLaws LLP may rely upon the opinion of Paul, Weiss, Rifkind, Wharton & Garrison LLP.

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        Based on information provided to us, the partners and associates of Parlee McLaws LLP as a group beneficially own, directly or indirectly, less than one percent of our outstanding securities and none of our securities or our property are to be received by such persons.

EXPERTS

        Our consolidated balance sheets as at December 31, 2010 and 2009 and the related consolidated statements of earnings, changes in shareholders' equity, comprehensive income and cash flows for each of the years in the three-year period ended December 31, 2010, incorporated in this prospectus supplement and the accompanying prospectus, have been so incorporated in reliance on the report dated March 1, 2011 of PricewaterhouseCoopers LLP, given on the authority of said firm as experts in auditing and accounting. PricewaterhouseCoopers LLP is independent in accordance with the Rules of Professional Conduct of the Institute of Chartered Accountants of Alberta and the rules of the SEC.

        Sproule Associates Limited, Sproule International Limited and GLJ Petroleum Consultants Ltd., independent qualified reserves evaluators, have evaluated our reserves in reports with an effective date of December 31, 2010 and a preparation date of February 14, 2011, as more particularly described in our Annual Information Form for the year ended December 31, 2010, incorporated by reference herein. The statements as to our reserves, which appear in or are incorporated by reference herein, have been so included or incorporated by reference upon the authority, as experts, of Sproule Associates Limited, Sproule International Limited and GLJ Petroleum Consultants Ltd., to the extent described herein or in the documents incorporated by reference herein.

        Based on information provided by the relevant persons or companies, there are beneficial interests, direct or indirect, in less than one percent of our securities or property or securities or property of our associates or affiliates held by Sproule Associates Limited, Sproule International Limited or GLJ Petroleum Consultants Ltd. or by "designated professionals", being any partners, employees or consultants of such independent consultants who participated in and who were in a position to directly influence the preparation of the relevant report, or any such person who, at the time of the preparation of the report was in a position to directly influence the outcome of the preparation of the report.

ENFORCEABILITY OF JUDGMENTS

        Since a significant portion of our assets, as well as the assets of a number of our directors and officers, are outside the United States, any judgment obtained in the United States against us or certain of our directors or officers, including judgments with respect to the payment of principal on any debt securities, may not be collectible within the United States.

        We have been informed by Parlee McLaws LLP that the laws of the Province of Alberta and the federal laws of Canada applicable therein permit an action to be brought in a court of competent jurisdiction in the Province of Alberta on any final and conclusive judgment in personam of any New York Court against us, which judgment is subsisting and unsatisfied for a sum certain with respect to enforceability of the Indenture and the notes that is not impeachable as void or voidable or otherwise ineffective under the internal laws of the State of New York if (i) the New York Court rendering such judgment had jurisdiction over the judgment debtor, as recognized by the courts of the Province of Alberta (and submission by us in the Indenture to the jurisdiction of the New York Court will be sufficient for that purpose with respect to the notes), (ii) the judgment debtor was properly served in connection with any action leading to such judgment, (iii) such judgment was not obtained by fraud or in a manner contrary to natural justice and the enforcement thereof would not be inconsistent with public policy, as such terms are understood under the laws of the Province of Alberta and enforcement thereof will not be contrary to any order made by the Attorney General of Canada under the Foreign Extraterritorial Measures Act (Canada) or by the Competition Tribunal under the Competition Act (Canada), (iv) the enforcement of such judgment would not be contrary to the laws of general

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application limiting the enforcement of creditors' rights including any other rule of law, whether equitable, legal or statutory, bankruptcy, reorganization, winding up, moratorium and similar laws and does not constitute, directly or indirectly, the enforcement of foreign revenue, expropriatory, penal or public laws in the Province of Alberta, (v) no new admissible evidence relevant to the action is discovered prior to the rendering of judgment by the court in the Province of Alberta, (vi) interest payable on the debt securities is not characterized by a court in the Province of Alberta as interest payable at a criminal rate within the meaning of section 347 of the Criminal Code (Canada) and (vii) the action to enforce such judgment is commenced within the appropriate limitation periods, except that any court in the Province of Alberta may only give judgment in Canadian dollars. We have been advised by such counsel that there is doubt as to the enforceability in Canada in original actions, or in motions to enforce judgments of United States courts, of civil liabilities predicated solely upon United States federal securities laws.

DOCUMENTS INCORPORATED BY REFERENCE

        This prospectus supplement is deemed to be incorporated by reference into the prospectus solely for the purposes of the offering of the notes. Other documents are also incorporated or deemed to be incorporated by reference into the prospectus. The following documents which have been filed with the securities commission or similar authority in each of the provinces and territories of Canada or the SEC are also specifically incorporated by reference in and form an integral part of the prospectus, as supplemented by this prospectus supplement:

•

our unaudited comparative consolidated financial statements for the three and nine month periods ended September 30, 2011, including the notes thereto, and accompanying Management's Discussion and Analysis.

        Any statement contained in this prospectus, in this prospectus supplement or in any document (or part thereof) incorporated by reference, or deemed to be incorporated by reference, into the prospectus for the purpose of the offering of the notes offered hereby shall be deemed to be modified or superseded to the extent that a statement contained in this prospectus supplement or in any other subsequently filed document (or part thereof) that also is, or is deemed to be, incorporated by reference in the prospectus modifies or supersedes that statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute part of this prospectus supplement or the prospectus. The modifying or superseding statement need not state that it has modified or superseded a prior statement or include any other information set forth in the document which it modifies or supersedes.

        You may obtain a copy of the financial statements and Management's Discussion and Analysis and other information identified above by writing or calling us at the following address and telephone number:

Canadian Natural Resources Limited
2500, 855 - 2 Street S.W.
Calgary, AB T2P 4J8
(403) 517-6700
Attention: Corporate Secretary

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CONSENT OF PRICEWATERHOUSECOOPERS LLP

        We have read the prospectus supplement dated                , 2011 to a prospectus dated October 28, 2011 with respect to the distribution of US$                of        % Notes and US$                of        % Notes of Canadian Natural Resources Limited ("CNRL"). We have complied with Canadian generally accepted standards for an auditor's involvement with offering documents.

        We consent to the incorporation by reference in the above-mentioned prospectus of our report to the shareholders of CNRL on the consolidated balance sheets of CNRL as at December 31, 2010 and 2009 and the related consolidated statements of earnings, changes in shareholders' equity, comprehensive income and cash flows for each of the years in the three year period ended December 31, 2010 and our report on the effectiveness of internal control over financial reporting as of December 31, 2010. Our reports are dated March 1, 2011.

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Base Shelf Prospectus

October 28, 2011

CANADIAN NATURAL RESOURCES LIMITED

Debt Securities

        Canadian Natural Resources Limited may offer for sale from time to time debt securities in the aggregate principal amount of up to US$3,000,000,000 or its equivalent in any other currency or units based on or relating to foreign currencies during the 25 month period that this prospectus (including any amendments hereto) remains effective.

        We will provide the specific terms of these securities and all information omitted from this prospectus in supplements to this prospectus. You should read this prospectus and the supplements carefully before you invest.

        Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

        We are permitted to prepare this prospectus in accordance with Canadian disclosure requirements, which are different from those of the United States. We prepare our financial statements in accordance with Canadian generally accepted accounting practices, and they are subject to Canadian auditing and auditor independence standards. They may not be comparable to financial statements of United States companies.

        Owning the debt securities may subject you to tax consequences both in the United States and Canada. This prospectus or any applicable prospectus supplement may not describe these tax consequences fully. You should read the tax discussion in any applicable prospectus supplement.

        Your ability to enforce civil liabilities under the United States federal securities laws may be affected adversely because we are incorporated in Alberta, some of our officers and directors and some of the experts named in this prospectus are Canadian residents, and many of our assets are located in Canada.

        The debt securities offered hereby have not been qualified for sale under the securities laws of any province or territory of Canada and are not being and may not be offered or sold, directly or indirectly, in Canada or to any resident of Canada in contravention of the securities laws of any province or territory of Canada.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

        In this prospectus, unless otherwise specified or the context otherwise indicates, references to "Canadian Natural", "us", "we" or "our" mean Canadian Natural Resources Limited and its subsidiaries, including its material operating subsidiaries and, where applicable, their respective interests in partnerships and other entities. Unless otherwise specified, all dollar amounts contained in this prospectus are expressed in Canadian dollars, and references to "dollars", "Cdn$" or "$" are to Canadian dollars and all references to "US$" are to United States dollars.

        All financial information included and incorporated by reference in this prospectus is determined using generally accepted accounting principles which are in effect from time to time in Canada, referred to as "Canadian GAAP". "U.S. GAAP" means generally accepted accounting principles which are in effect from time to time in the United States.

        This prospectus replaces our base shelf prospectus dated October 9, 2009.

        This prospectus is part of a registration statement on Form F-9 relating to the debt securities that we filed with the U.S. Securities and Exchange Commission (the "SEC"). Under the shelf registration statement, we may, from time to time, sell any combination of the debt securities described in this prospectus in one or more offerings up to an aggregate principal amount of US$3,000,000,000. This prospectus provides you with a general description of the debt securities that we may offer. Each time we sell debt securities under the registration statement, we will provide a prospectus supplement that will contain specific information about the terms of that offering of debt securities. The prospectus supplement may also add, update or change information contained in this prospectus. Before you invest, you should read both this prospectus and any applicable prospectus supplement together with additional information described under the heading "Where You Can Find More Information". This prospectus does not contain all of the information set forth in the registration statement, certain parts of which are omitted in accordance with the rules and regulations of the SEC. You should refer to the registration statement and the exhibits to the registration statement for further information with respect to us and the debt securities.

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