EXHIBIT 10 ---------- [LETTERHEAD OF SPROULE ASSOCIATES LIMITED] SPROULE ASSOCIATES LIMITED Ref.: 1808.14933 March 29, 2004 Mr. Larry Galea, Manager, Operations Planning Canadian Natural Resources Limited 2500, 855 Second Street SW Calgary AB T2P 4J8 RE: CONSENT OF INDEPENDENT PETROLEUM CONSULTANTS Dear Mr. Galea: We consent to the use of our report with respect to the reserves data of Canadian Natural Resources Limited incorporated by reference in its (i) Annual Report (Form 40-F) for the year ended December 31, 2003 and (ii) Registration Statement on Form F-9 (Registration No. 333-104919), filed with the Securities and Exchange Commission. Sincerely, /s/ Harry J. Helwerda ------------------------------ Harry J. Helwerda, P.Eng. Vice-President, Engineering, Canada and U.S. HJH:db 900, 140 Fourth Ave SW; Calgary AB T2P 3N3 Canada; Tel: (403) 294-5500, Fax: (403) 294-5590 1675 Broadway, Suite 1130, Denver CO 80202 U.S.A.; Tel: (303) 592-8770, Fax: (303) 592-8771 1001 Fannin, Suite 550, Houston TX 77002 U.S.A.; Tel: (713) 652-5140, Fax: (713) 652-5143 Toll Free: 1-877-777-6135 info@sproule.com, www.sproule.com