Gulf Keystone Petroleum Regulatory News (GKP)

Not for release, publication or distribution in or into the United States or jurisdictions other than the United Kingdom and Bermuda where to do so would constitute a contravention of the relevant laws of such jurisdiction.

11 August 2010

Gulf Keystone Petroleum Ltd. (AIM: GKP)

("Gulf Keystone" or "the Company")

Ten Fold Increase in Mus Test Rates During

Jurassic Zone Testing on the Shaikan-1 Discovery Well

Gulf Keystone announces the results of further testing of the Mus (1,627m to 1,667m) section of the Jurassic on its Shaikan-1 discovery well. Final, stable, production rates during this week's re-test, using a much improved test setup versus the original 2009 test, were measured at 1,250 bopd with an API gravity of 19.7 degrees and a gas oil ratio (GOR) of 10 standard cubic feet per barrel of oil at a flowing wellhead pressure of 50 psi. This natural flow rate represents a ten fold increase over the 128 bopd measured during the initial test in 2009.

Tests using a low capacity electric submersible pump (ESP), resulted in rates up to 2,250 bopd.

The workover rig will now begin operations to complete the Shaikan-1 well in the Sargelu (1,450m to 1,510m) section of the Jurassic, and the well will be configured for long term production testing.

John Gerstenlauer, Chief Operating Officer for Gulf Keystone said "This retest of the Mus formation demonstrates that even this very low GOR zone is capable of substantial natural flow production rates when properly configured. In addition, it gives us further encouragement for future development, having demonstrated significantly increased production values even with a low capacity ESP."

Enquiries:

or visit: www.gulfkeystone.com

John Gerstenlauer, the Company's Chief Operating Officer, who has 31 years of relevant experience within the sector meets the criteria of a qualified person under the AIM note for mining, oil and gas companies and has reviewed and approved the technical information contained in this announcement. Mr. Gerstenlauer is a member of the Society of Petroleum Engineers.

Notes to Editors:

§ Gulf Keystone Petroleum Ltd. (AIM: GKP) is an independent oil and gas exploration company focused on exploration in the Kurdistan region of Northern Iraq.

§ Gulf Keystone Petroleum International (GKPI) holds Production Sharing Contracts for fourexploration blocks in Kurdistan.

§ The Company's shares have traded on the AIM market, since listing on 8 Sept 2004.

§ Gulf Keystone Petroleum Limited is registered in Hamilton, Bermuda with offices in Erbil, Kurdistan, Algiers, Algeria and London, UK.

Not for release, publication or distribution, directly or indirectly, in or into the United States or jurisdictions other than the United Kingdom and Bermuda where to do so would constitute a contravention of the relevant laws of such jurisdiction. This document (and the information contained herein) does not contain or constitute an offer of securities for sale, or solicitation of an offer to purchase securities, in the United States or jurisdictions other than the United Kingdom and Bermuda where to do so would constitute a contravention of the relevant laws of such jurisdiction. The securities referred to herein have not been and will not be registered under the US Securities Act of 1933, as amended (the "Securities Act"), and may not be offered or sold in the United States unless the securities are registered under the Securities Act, or an exemption from the registration requirements of the Securities Act is available. No public offering of the securities will be made in the United States.