Exhibit 23.8
[GLJ Petroleum Consultants Ltd. Letterhead]
LETTER OF CONSENT
TO: Mr. Martin H. Eden
Chief Financial Officer
Gran Tierra Energy Inc.
300, 611 - - 10th Ave, SW
Calgary, Alberta T23R 0B2
Canada
Re: Gran Tierra Registration Statements:
Form S-3
Filed with the U.S. Securities Exchange Commission
As the independent reserve engineers for Gran Tierra Energy Inc. (Gran Tierra), GLJ Petroleum Consultants Ltd. hereby confirms that it has granted and not withdrawn its consent to the reference to GLJ’s review of Gran Tierra’s Costayaco Field reserves as of June 30, 2008 in the form and context incorporated by reference by Gran Tierra in this Form S-3 filed with the U.S. Securities and Exchange Commission. We also consent to the reference to us under the heading "Experts" in the Prospectus, which is part of this Registration Statement.
| Yours truly, |
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| GLJ PETROLEUM CONSULTANTS LTD. |
| |
/s/ Leonard L. Herchen Leonard L. Herchen, P. Eng. Manager, Engineering |
Dated: January 12, 2009
Calgary, Alberta
CANADA
