3D Seismic Interpretation

Rockhopper Exploration plc
18 February 2008


                                                                          

PRESS RELEASE


18 February 2008

           Rockhopper Exploration plc ('Rockhopper' or 'the Company') 
                        3D Seismic Interpretation Update


   •Prospect Mapping Completed

   •5 hydrocarbon plays identified

   •Prospects could contain over 1.9 billion barrels recoverable

   •Technical work moving to the next stage

   •Substantial increase in drillable targets

Rockhopper is pleased to announce the results of the initial phase of mapping of
prospects in its North Falkland Basin licences, PL032 and PL033, where 850km2 of
3D seismic data were collected in 2007. It is estimated by the Directors of
Rockhopper that the prospects identified could contain 1.9 billion barrels
unrisked recoverable and have P50 unrisked recoverable reserves of circa 1.2
billion barrels. This list of prospects does not include a number of additional
leads which are still being investigated. In addition, prospects have already
been identified on licences PL023 and PL024 which the Directors believe have P50
unrisked recoverable reserves of 2.5 billion barrels.

The new mapping has identified five hydrocarbon plays in the acreage and
confirmed the presence of multiple drilling targets. In addition, the 3D seismic
has revealed that one of the exploration wells drilled by Shell in 1998 which
(amongst other oil shows) encountered a thin sand with good hydrocarbon shows,
is actually located at the very edge of a fan prospect which appears to thicken
towards its centre. The Directors now believe that this thicker part of the fan
prospect could therefore contain commercially viable accumulations of
hydrocarbons.

The acreage, now held 100% by Rockhopper was previously held by Shell and two
wells were drilled in 1998. Well 14/5-1 found oil and gas shows, well 14/10-1
recovered live oil to the surface. The Rockhopper 2007 3D seismic survey
overshot the well locations and also the unexplored eastern basin margin which
is currently an untested oil play.

The data confirm the prospectivity of the acreage and have further reduced the
exploration risk as more play types have been identified.

Rockhopper will now commence advanced work on the data which will include AVO
analysis, imaging studies, geochemical modelling, further detailed log analysis,
depth conversion and reservoir modelling.

A table of prospect sizes and additional technical commentary on the play types
is attached as an appendix.

Rockhopper's Executive Chairman, Dr. Pierre Jungels, commented:

'The quality of the 3D seismic data and the further insight into the basin it
has allowed us is extremely encouraging. In my experience, we now have a very
high quality prospect inventory from which to select a number of drilling
locations. Work will now focus on refining the prospect inventory, including
those previously identified in licences PL023 and PL024, in preparation for
drilling or farming out.

In fairly shallow waters such as we have on this acreage, modern drilling
techniques, subsea wells and FPSO technology allow stand alone development of
structures smaller than the majority of those identified.

We now have sufficient drilling targets to justify a drilling campaign, whether
that means farming out or obtaining a rig as operator. Now that we have a larger
number of potential drillable targets we can also begin to accelerate our search
for a rig.'


NB: This statement has been approved by the Company's geological staff who
include David Bodecott (Exploration Director), who is a Member of Petroleum
Exploration Society of Great Britain (PESGB) and the American Association of
Petroleum Geologists (AAPG) with over 30 years of experience in petroleum
exploration and management, for the purpose of the Guidance Note for Mining, Oil
and Gas Companies issued by the London Stock Exchange in respect of AIM
companies, which outline standards of disclosure for mineral projects.



For further information, please contact:


Rockhopper Exploration plc            www.rockhopperexploration.co.uk
Sam Moody - Managing Director         01722 414 419


Aquila Financial Ltd                  www.aquila-financial.com
Peter Reilly                          0118 979 4100
Yvonne Fraser


Landsbanki Securities (UK) Limited    www.landsbanki.co.uk
Tom Hulme                             020 7426 9000


Technical Appendix


Recoverable oil
Millions of barrels
Unrisked

Play Type         Prospect Name                   P50               P10

Pinchout
                  Sedge                            68                93
                  Tyssen                           24                24
                  Jason                           132               202

Fans
                  Sea Lion                        154               350
                  Chatham                         106               188

Downthrown Closures

                  Pembroke                          9                18
                  Howard                            8                20
                  Meredith                         14                20

                  Walker*                          21                 *
                  Louis*                           90               217

                  Bull                             76                76
                  Fox                              76               156
                  Stephens                         78                78
                  Darwin                           40                61

Intra Basinal Structures
                  Johnson                         125               210

Central Basin Inversion
                  Berkeley                        130               200
                  George                           21                63

          TOTAL                                  1170              1977



*Walker and Louis are a single prospect at P10, but separate smaller prospects
at P50


The five hydrocarbon plays are as follows:


1. Basin Margin Pinchout.

The pinchout of the deltaic unit (sand unit penetrated by the Shell wells)
against the basement high that forms the eastern basin margin. Both Shell wells
proved this unit at locations within the basin centre and indicated good
reservoir characteristics with porosities of up to 30%.

The pinch out play may be more advantageously placed for hydrocarbon charge from
the large basin margin fault system than the original target of the Shell wells
which were in the centre of the basin.

2. Sand-rich Fan systems.

A number of fans have been identified at several stratigraphic levels.

Further interpretation work is required to establish the nature and significance
of some of a large number of seismic high-amplitude events associated with these
reservoir systems.

The Sea Lion fan, issued from two input points along the eastern basin margin
and was not tested by either of the Shell wells. This coalescing fan system is
defined by a zone of amplitude brightening in a structural and depositional low.

The Chatham fan, which is a north-south prograding system characterised by
elongate channel-attached lobes, appears to have been tested at its edge by the
second Shell well (14/10-1). A 1m thick sand was encountered in this well having
very good C1 to C5 hydrocarbon shows. The fan appears to thicken away from the
well into an area of very bright seismic amplitudes. This suggests that
commercially viable accumulations of hydrocarbons could be present in the
brighter areas of the fan which have not yet been tested. These areas will be
further investigated for prospectivity during further technical work.

3. Basin margin Downthrown Closures.

Several seismic intervals form substantial closed structures along the hanging
wall (downthrown flank) of the huge eastern margin fault system. Amplitude
anomalies are associated with some of the mapped levels and additional technical
work will resolve the significance of these.

The downthrown basin margin play is completely untested in the North Falkland
Basin and it has always been recognised as a play that can be readily charged by
hydrocarbons generated from the mature base of the organic-rich Post-rift source
sequence. The Shell wells proved that the Post-rift source is mature in this
area of the North Falkland Basin.

4. Intra-basinal Structural highs.

Structural closures independent of the basin margin fault. One very large such
prospect has been identified. Additional work is required on this target as it
extends beyond the area of 3D coverage and the reserve estimate here includes
only the element of the prospect covered by the 3D. This is separate to the
basin centre inversion structure tested by the Shell wells.

5. Central basin inversion high related prospects

Shell drilled a large basin centre inversion structure in 1998. While both wells
were commercial failures at that time (with oil at USD12 per barrel) they did
prove the existence of hydrocarbons in the area (both oil and gas). The Shell
structure is so large that a number of untested prospects may exist in flanking
areas, some of which are also related to fans and amplitudes not tested by the
previous wells. Targets have been identified to the North, West and South of the
Shell wells related to the same structure which was not exhaustively tested by
the two wells in 1998.



Notes to editors

www.rockhopperexploration.co.uk

The Rockhopper Group started trading in February 2004 to invest in and carry out
an offshore oil exploration programme to the north of the Falkland Islands. The
Group, floated on AIM in August 2005, is currently the largest licence holder in
the North Falkland Basin and has a 100 per cent. interest in four offshore
production licences which cover approximately 3,800 sq. km. These licences have
been granted by the Falkland Islands government.








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