New Well Data Upgrades Prospect – Addition

NORTHERN PETROLEUM PLC - New Well Data Upgrades Prospect – Addition

PR Newswire

London, March 19

Embargoed for immediate release 19th March 2013.

This announcement replaces announcement 30940-FE0B which was released at 9.40amthis morning. The only change to the announcement is the addition of thecompetent person's estimate of chance of success for the Cygnus prospect in thethird paragraph. The full text of the competent person's letter is available onthe Company's website. The full text of the amended release is set out below.

Northern Petroleum Plc (AIM: NOP) announces that the Cygnus prospect offshoreItaly has now been mapped as an estimated unrisked prospective resource of upto 790 million barrels of recoverable oil within Northern's 100% owned F.R39.NPpermit. The prospect is adjacent to and up-dip of the producing Aquila oilfield. This prospective resource estimate is based upon the Cygnus prospectsharing a common oil water contact with Aquila. The work was undertaken by ERCEquipoise Ltd ("ERCE"). Northern's mapping of the available 2D seismic data hasnot found a separation or barrier from the producing Aquila oil wells.

The ERCE work was commissioned in January this year, following the publicationof previously undisclosed well data relating to the Aquila oil field in anenvironmental submission by its operator, ENI S.p.A ("Eni"). The Aquila wellsare located in the production concession adjacent to permit F.R39.NP. It is theknowledge of the deeper oil water contact in those wells that increases theestimated prospective resources of the Cygnus prospect if it is proven to havethe same oil water contact as the Aquila oil field.

The prospect trap for Cygnus is predominantly stratigraphic with the samereservoir as the Aquila field, consisting of Cretaceous resedimented carbonatesderived from the Apulian platform. In their estimates ERCE recognise that it ispossible for the Aquila field to be in charge communication with the Cygnusprospect and therefore have a common oil water contact with the Aquila field.This results in a High (P10) case of 978 million barrels, with 790 millionbarrels in Northern's permit F.R39.NP. The Low (P90), Best (P50) and Mean casesuse shallower contacts giving partial hydrocarbon fill of the mapped prospectand a separation of the Aquila field from the Cygnus prospect. ERCE hasestimated a mean prospective resource of 446 million barrels, of which 401million barrels is within the permit and the remainder beyond the permitboundary. ERCE estimate a chance of success of 12% for the Cygnus prospect.

The Cygnus prospect, the nearby similar Corvus prospect and the Rovesti oildiscovery are the targets of a 3D seismic programme planned for acquisitionthis year following the receipt of currently pending environmental approvals.Northern has now started the process of collating the data for the submissionof a environmental impact assessment for regulatory approval in relation todrilling an exploration well on the Cygnus prospect.

The agreement with Azimuth Limited announced on 25th March 2011 involvingpermits F.R39.NP and F.R40.NP has now lapsed. Northern has entered intodiscussions with a number of parties to join with Northern in the proposed 3Dseismic survey and, more importantly, to drill and test a well on the Cygnusprospect.

Derek Musgrove, Managing Director of Northern, stated:

"This project is materially valuable to shareholders and our efforts in Italyhave now been concentrated upon this. Discussions are currently progressingwith major industry partners to join with Northern to drill the prospect.

The availability of the new Aquila well data has greatly increased ourconfidence levels in the Cygnus prospect. Yet further, ERCE have independentlyconfirmed the Cygnus prospect as being a very significant prospective resourcethat has in the upside case the potential to be close to a billion barrels ofrecoverable oil based on a common oil water contact with the Aquila field.

We have been working on this for some time and it is greatly pleasing that theindependent work shows that the permit has a potential of having significantvalue to shareholders. We continue to see our efforts in Italy being focussedupon seeing it drilled."

In accordance with the AIM Rules - Guidance for Mining and Oil & Gas Companies,the information contained in this announcement has been reviewed and signed offby the Exploration and Technical Director of Northern, Mr. Graham Heard CGeol.FGS, who has over 35 years experience as a petroleum geologist. He hascompiled, read and approved the technical disclosure in this regulatoryannouncement. The technical disclosure in this announcement complies with theSPE/WPC standard.

The full letter from ERCE is available on the Northern website(www.northpet.com).

Glossary

STOIIP Stock tank oil initially in place

Prospective resources

Prospective resources are those quantities of petroleum which are estimated, asof a given date, to be potentially recoverable from undiscovered accumulations.

Potential accumulations are evaluated according to their chance of discoveryand, assuming a discovery, the estimated quantities that would be recoverableunder defined development projects. It is recognised that the developmentprogrammes will be significantly less detail and depend more heavily onanalogue developments in the earlier phases of exploration.

The range of uncertainty of the recoverable and/or potentially recoverablevolumes may be represented by either deterministic scenarios or by aprobability distribution. When the range of uncertainty is represented by aprobability distribution, a low, best, and high estimate shall be provided suchthat:

• There should be at least a 90% probability (P90) that the quantities actuallyrecovered will equal or exceed the low estimate.

• There should be at least a 50% probability (P50) that the quantities actuallyrecovered will equal or exceed the best estimate.

• There should be at least a 10% probability (P10) that the quantities actuallyrecovered will equal or exceed the high estimate.

When using the deterministic scenario method, typically there should also below, best, and high estimates, where such estimates are based on qualitativeassessments of relative uncertainty using consistent interpretation guidelines.Under the deterministic incremental (risk–based) approach, quantities at eachlevel of uncertainty are estimated discretely and separately.

For further information please contact:

Northern Petroleum Plc Tel: +44 (0)20 7469 2900

Derek Musgrove, Managing Director

Graham Heard, Exploration and Technical Director

Westhouse Securities (Nomad and Broker) Tel: +44 (0)20 7601 6100

Richard Baty / Petre Norton - Corporate Finance

Ian Napier - Corporate Broking

FTI Consulting Tel: +44 (0)20 7831 3113

Billy Clegg / Victoria Huxster

Bishopsgate Communications Tel: +44(0)20 7562 3350

Nick Rome

Notes to Editors:

Northern is a full cycle oil and gas company currently holding numerouslicences in a number of low risk areas and is continuing with its strategy ofadding and securing value for shareholders as it engages with projects at allstages of the E&P value chain.

Comprehensive information on Northern and its oil and gas operations, includingall press releases, annual reports and interim reports are available fromNorthern's website at www.northpet.com.