PCI.L Regulatory News (PCI)

Dublin

21st March 2011

Petroceltic International plc

Results of AT-5 Pilot Hole Logging

Petroceltic International plc ("Petroceltic" or "the Company"), the upstream oil and gas exploration and production company focused on the Middle East, North Africa and the Mediterranean, is pleased to announce that it has completed logging and drilling of well AT-5 (pilot hole) on the Isarene permit in Algeria. Drilling began at the AT-5 well on 9th January 2011, and the well reached its total depth of 2049m on 2nd March 2011, having experienced drilling delays due mainly to surface equipment failures on the contracted drilling rig.

Well AT-5 is being drilled to test a major "pop-up" feature in the north of the field and is located approximately 4 km east of the AT-1 well. The "pop-up" feature is one of many such structures typical of the northern part of the field and it is anticipated that these features are associated with high natural fracture density and thus potentially enhanced un-stimulated gas productivity. Mud losses while drilling, together with core, conventional logs and image logs from AT-5 all indicate the interval is potentially highly fractured with some of these being open natural fractures.

Logs at AT-5 showed the objective Ordovician reservoir to be fully gas bearing, and a gross gas column of 75.5 metres was logged, with no gas water contact seen in the well. The overall hydrocarbon pore volumes encountered at this location were significantly in excess of the pre-drilling prognosis. The well was cored with 29 metres of core being recovered from the objective reservoir section.

After completion of coring, drilling, logging and borehole image logging of the near vertical AT-5 pilot well, the well has now been side-tracked as originally planned (AT-5Z) and a horizontal section of up to 500 metres is currently being drilled to explore for high natural fracture density associated with a series of tectonic faults. The faults have been interpreted from 3D seismic data and the horizontal well is oriented to intersect fractures which are expected to be open.

Brian O'Cathain, Chief Executive of Petroceltic commented:

"The results of well AT-5 are encouraging to date, the presence of natural fractures at this location augurs well for the test results, and the overall gas column logged was greater than expected at this location. We are looking forward to the AT-5Z well test results, now expected in May 2011."

Press Enquiries to:

Brian O'Cathain/ Alan McGettigan, Petroceltic International Tel: +353 (1) 421 8300

Philip Dennis, Pelham Bell Pottinger Tel: +44 (20) 7861 3919

Joe Murray / Joe Heron, Murray Consultants Tel: +353 (1) 4980300

Hugh McCutcheon / John Frain, Davy Tel: +353 (1) 679 6363

Dr. Dermot Corcoran, Head of Exploration, Petroceltic International plc, is the qualified person who has reviewed and approved the technical information contained in this announcement. Dr. Corcoran has a B.Sc in Geology, a M.Sc. in Geophysics, and a Masters degree in Business Administration, all from the National University of Ireland, Galway. He also holds a Ph.D in Geology from Trinity College, Dublin. Dr. Corcoran has over 20 years experience in oil & gas exploration and production, and has previously worked at ExxonMobil, the Petrofina Group, and Statoil.

Notes to Editors:

Petroceltic International plc is a leading Upstream Oil and Gas Exploration and Production Company, focused on the Middle East, North Africa and Mediterranean area, and listed on the London Stock Exchange's AIM Market and the Irish Sock Exchange's ESM Market. The Company has exploration assets in Algeria, Tunisia and Italy. Petroceltic is in a unique position in Algeria, operating a significant licence in partnership with Sonatrach the state oil company, one of only two AIM listed companies to enjoy this position.

The Ain Tsila discovery was made by Petroceltic in 2009 and was reported by IHS/Herold as the 10th largest discovery made worldwide in 2009.

A diagram depicting the location of the AT-5 and AT-5Z well location within the Isarene permit in included as slide 24 of the "oil barrel" presentation on the company's website, www.petroceltic.ie.