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.

10 August 2011

Gulf Keystone Petroleum Ltd. (AIM: GKP)

("Gulf Keystone" or "the Company")

Sheikh Adi Preliminary Resource Evaluation

Gulf Keystone announces today results of an independent preliminary evaluation of the Sheikh Adi resources by Dynamic Global Advisors (DGA), independent Houston-based exploration consultants.

The DGA report, based on Sheikh Adi-1 wireline logging data, core samples, 2D and 3D seismic and regional data, has indicated a significant range of between 1 billion barrels and 3 billion barrels of gross oil-in-place volumes calculated on the P90 to P10 basis, with a P50 estimate of 1.9 billion barrels.

Gulf Keystone has completed drilling of Sheikh Adi-1, the first exploration well to be drilled on the Sheikh Adi structure, to a TD (total depth) of 3,780 meters in the Triassic zone. A series of flow tests will now be performed on a number of Jurassic zones in the Sheikh Adi-1 well. Testing in the Triassic zone will not be possible due to issues relating to casing integrity at these depths.

The Sheikh Adi block is located immediately to the west of the Company's Shaikan block, where a major discovery was made in 2009. Gulf Keystone is the Operator of the Sheikh Adi block with an 80 percent working interest and is carrying the Kurdistan Regional Government's 20 percent working interest in the block.

DGA's previous assessments of assets on behalf of Gulf Keystone included independent evaluation of the Shaikan discovery, including a major revision of the gross oil-in-place volumes (4.9 billion barrels to 10.8 billion barrels calculated on the P90 to P10 basis) announced in April 2011.

John Gerstenlauer, Gulf Keystone's Chief Operating Officer commented:

"This independent report demonstrates the potential of the Sheikh Adi block with between 1 and 3 billion barrels of gross oil-in-place. This report reinforces our belief in having encountered yet another potential world class oil source. We plan to further evaluate the Sheikh Adi structure and define and assess this complicated geological structure. The Sheikh Adi oil-in-place numbers are all the more significant due to our 80 percent interest in the block. These numbers are in addition to 7.5 billion barrels of P50 oil-in-place at Shaikan, 2.4 billion barrels of P50 oil-in-place at Akri-Bijeel and 1.9 billion barrels of estimated petroleum-initially-in-place at Ber Bahr. This report further demonstrates the world class nature of Gulf Keystone's assets in the Kurdistan Region of Iraq".

Enquiries:

or visit: www.gulfkeystone.com

John Gerstenlauer, the Company's Chief Operating Officer, who has 31 years of relevant experience within the sector and meets the criteria of a qualified person under the AIM note for mining, oil and gas companies, 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 and production company focused on exploration in the Kurdistan Region of 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 of the London Stock Exchange since listing on 8th September 2004.

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

§ Oil initially-in-place (or petroleum-initially-in-place) is that quantity of petroleum that is estimated, as of a given date, to be contained in known accumulations prior to production. The range of uncertainty of the oil-in-place (petroleum-initially-in-place) volumes is represented by a probability distribution with a low, mid and high provided: P90 represents at least a 90% probability (high) that the quantities determined to be in place will equal or exceed the low estimate; P50 represents at least a 50% probability (mid) that the quantities determined to be in place will equal or exceed the mid estimate; and P10 represents at least a 10% probability (low) that the quantities determined to be in place will equal or exceed the high estimate. A P1 estimate of quantities determined to be in place represents at least a 1% probability that this estimate will be equaled or exceeded.

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.