17 December 2014

                                 Doriemus plc
                         ("Doriemus" or the "Company")

                       Horse Hill-1 Oil Discovery Update

            Upgrade on Portland Discovered Oil in Place Volumes and
        Conventional Upper Jurassic Limestone Oil Play, Weald Basin UK

Doriemus Plc (AIM: DOR) today announces that, as a result of the analysis and
integration of subsurface data from the Horse Hill-1 ("HH-1") discovery well,
in which it holds a net attributable interest of 6.5%, the calculated estimates
of the discovered most likely gross oil initially in place ("OIIP") within the
overall Upper Portland sandstone conventional reservoir in the HH-1 and
Collendean Farm-1 ("CF-1") structure have increased by over 250% from the 3.1
million barrels ("mmbbls") reported on 24 October 2014, to a current most
likely OIIP of 8.2 mmbbls. Similarly, calculated estimates of low case (P90)
discovered OIIP has increased by nearly 400% to 5.7 mmbbls and high case (P10)
OIIP volumes show a 250% increase to 12.1 mmbbls.

In addition, the results of electric log analysis in the HH-1, CF-1 and other
regional wells to the south of PEDL 137 ("Licence"), combined with ongoing
geochemical analysis of HH-1 samples, indicate that the key elements of a
conventional Upper Jurassic Limestone oil play have been demonstrated to extend
into the southern part of the Licence. The HH-1 well demonstrates the presence
of limestone porosity adjacent to, both overlying and underlying, thermally
mature super-saturated world-class oil source rocks within a 1,496-foot gross
interval of the Upper Jurassic Kimmeridgian Clay ("KC") Formation between 2,224
feet and 3,720 feet TVDss. Samples from the KC show total organic carbon
("TOC") of up to 9.4%, generative potentials of between 45-103 kg of
hydrocarbons per tonne and with measured vitrinite reflectance ("Ro") exceeding
0.81% at the base of the formation.

Further conventional oil potential within the Middle Jurassic Kellaways Beds
sandstones in HH-1 is currently under investigation.

Work is underway to obtain the necessary permissions to conduct a production
flow test from the HH-1 Upper Portland conventional oil pool in 2015.

The current OIIP estimates are set out in Table 1 below.

The full results of the HH-1 well are complex by their nature. The operator's
post-well evaluation has therefore taken longer than expected and is still
continuing, as described below.

Portland Sandstone Discovery

Integration of the Vertical Seismic Profile ("VSP") data from the HH-1 well has
enabled a revised interpretation of available 2D seismic data to be made over
the geological structure containing the HH-1 discovery. The current seismic
interpretation is strongly indicative that the Upper Portland oil pool,
discovered by HH-1, is most likely part of a larger geological structure
containing the CF-1 well to the north drilled by Esso in 1964.

New electric log analysis of the CF-1 well demonstrates that a near identical
Upper Portland reservoir section to that seen in HH-1 exists with a gross
97-foot oil saturated "missed oil pay" section and average porosities of 16%.
The Company reported on 24 October 2014 that HH-1 contained a gross oil
saturated Upper Portland section of 102 feet with 16% average porosity. Oil
saturations exist to the base of the Upper Portland sand reservoir in both HH-1
and CF-1, indicating that the oil water contact lies deeper within the
structure. The Company currently interprets that the proven lowest oil at 1,900
feet TVDss found in the HH-1 well now demonstrates that a most likely 140 feet
hydrocarbon column has been discovered, 38 feet greater than the 102-foot oil
column previously reported. The mapped spill point (and possible oil water
contact) of the combined HH-1 and CF-1 Upper Portland oil pool demonstrates
that a possible 240-foot maximum hydrocarbon column could exist within a
structural closure of approximately 3,400 acres (14 square kilometres).

The Operator's analyses of the Brockham-1 well logs demonstrate that the oil
producing Upper Portland reservoir thickness and overall quality in the nearby
Brockham field are very similar to HH-1 and CF-1 and provide a direct producing
reservoir analogue. However, the Operator's calculated most likely (P50) OIIP
of 8.2 mmbbl for the HH-1 and CF-1 discovery is significantly larger than the
Brockham field's most likely (P50) Upper Portland OIIP of 3.62 mmbbl, certified
by RPS Energy at end 2013.

Work is ongoing to submit an application to the Department of Energy and
Climate Change ("DECC"), the Environment Agency and Surrey County Council for
permission to carry out a flow test on the Upper Portland Sandstone in HH-1.
The planned flow test will likely include a pressure transient test to examine
the reservoir connectivity within the overall geological structure.

Subject to this HH-1 flow test, a future submission is planned to DECC of a
Field Development Plan for the HH-1 and CF-1 discovery. The presence of two
wells containing oil saturations down to base reservoir within the same mapped
structural closure, and with similar reservoir quality to the Brockham oil
field but larger OIIP, significantly increases the Company's confidence that
the Upper Portland discovery can be developed as a commercial oil field.

Table 1: Estimated gross in place discovered Upper Portland Sandstone oil
volumes

HH-1 and CF-1             Low (P90)        Medium (P50)         High (P10)
Structure

Discovered OIIP,mmbbls       5.7                8.2                12.1

Increase from 24.10.14      +380%              +260%               +250%

Doriemus has a net attributable interest of 6.5% in the discovery.

It should be noted that the OIIP numbers in Table 1, above, represent the
management's current viewpoint. For the avoidance of doubt OIIP numbers should
not be construed as resource or reserve estimates as a significant proportion
will not be recovered during any future production regime.

Volumes have been estimated by the Operator using methodologies and standards
published by the Society of Petroleum Engineers.

Conventional Upper Jurassic Limestone Oil Potential

The HH-1 well penetrated an unexpectedly thick 1,496-foot gross interval of the
Upper Jurassic Kimmeridge Clay ("KC") Formation between 2,224 feet and 3,720
feet TVDss. The sequence contains predominantly organically rich high gamma-ray
hot shale, inter-bedded with two regionally correlatable limestone units.
Preliminary examination of cuttings indicates the limestones are coccolithic
argillaceous micrites. The mud log showed elevated gas readings above the upper
limestone (KC Micrite 1) and weak oil shows were reported within the limestone.
The KC Micrite 1 encountered at 2,510.4 feet TVDss has a gross thickness of 113
feet and electric log analysis indicates the development of 37 feet of net
porosity greater than 5%. A continuous oil saturated zone of approximately 20
feet below 2,550 feet TVDss is calculated. Average total porosity within the
hydrocarbon zone is calculated at 6.4% and is dominated by secondary porosity.

The gamma-ray log through the KC Micrite 1 shows a near identical pattern and
formation thickness to the equivalent micrite found in the Balcombe-1 well,
drilled by Conoco in 1986 approximately 15 kilometres to the south. The
Operator's analysis also demonstrates that the top of the oil saturated porous
zone in HH-1 occurs at an identical stratigraphic and gamma-ray point to the
top of the proven tested oil pay zone in Balcombe-1. Total porosities of 8% are
calculated within the Balcombe pay section and are thus similar to HH-1.

The lower limestone (KC Micrite 2) has a gross thickness of 83 feet and shows
28.6 feet of net porosity development with an average porosity of 7%. No shows
or elevated gas readings were reported, although minor thin oil saturated zones
are calculated from logs.

The Company reported on 5 November 2014 that multiple oil shows and elevated
gas readings were encountered within the KC Formation and that preliminary
geochemical analysis showed oil source rock potential to likely be higher than
expected. Subsequent analysis of a further eight KC shale samples, from 2,715
to 3,345 feet TVDss encasing the KC micrites, show TOCs of 4.64 to 9.4% and
generative potentials of between 45 and 103 kg hydrocarbon/tonne of rock.
Corresponding calculated hydrogen indices (HI) are extremely high, ranging from
759-1098, indicating a very oil-prone source rock. These initial sample results
gives management confidence that the KC within the south of PEDL 137 has the
potential to be a world-class source rock of equivalence to the proven
conventional oil source rocks of the KC within the Viking Graben and Central
Graben of the North Sea.

Thermal maturation data obtained from well cuttings samples shows that the
pre-Oligocene and Jurassic section of the HH-1 well has achieved greater than
expected maximum burial depths. Measured vitrinite reflectance ("Ro") between
the top and base of the KC ranges from 0.62-0.81%, demonstrating that the KC
lies within the early to peak oil generation window. The Lower Liassic shale
and limestone sequence shows a measured Ro of up to 0.98%, indicating the late
peak oil to early wet-gas condensate generation window.

The 2014 Weald Shale Report by the British Geological Survey models the top of
the oil window within the Weald Basin to represent a burial depth of 7,000 to
8,000 feet (i.e. an Ro of 0.5-0.6%). Consequently, the top of the oil window,
interpreted to be at circa 2,300 feet TVDss in the HH-1 well, indicates the
well was likely to have been uplifted by approximately 4,500 to 5,500 feet
during the post-Oligocene inversion period. The southern part of PEDL 137
during KC deposition would thus have been in a more basin-centred location than
at present day and could lie within a high TOC KC basinal sweet-spot.

The Operator has concluded that the most likely source of oil saturations found
within the KC Micrite 1 is thus from the adjacent underlying and overlying hot
shale of the KC in direct proximity to the HH-1 well.

The Operator concludes that the presence of thermally mature KC source rocks,
together with porosity within the KC Micrites and log derived micrite oil
saturations, strongly indicate that an Upper Jurassic limestone conventional
play exists within the southern area of PEDL 137.

Further detailed integrated geochemical and petrophysical studies are ongoing
to help establish possible OIIP volumes in the KC Micrite 1. The Operator is
also currently evaluating the feasibility of a short flow test in the KC
Micrite 1 after the planned Upper Portland flow test.

Conventional Middle Jurassic Kellaways Beds Oil Potential

Re-examination of the HH-1 mud log shows that gas levels increase significantly
60 feet above the Kellaways Sandstone, continue throughout the 47-foot gross
sand interval and immediately drop off within the underlying Great Oolite
limestone. No observed oil shows were recorded within the Kellaways Sandstone.
Geochemical analyses of samples from the Oxford Clay demonstrate that the
section directly above the Kellaways Beds is thermally mature for oil
generation (Ro of greater than 0.81%) and contains potential generative oil
source rocks with TOCs of 1.9 to 2.9%. Electric logs are now being evaluated in
more detail, to determine whether potential oil saturations lie within the
Kellaways Sandstone.

Doriemus' interest in Horse Hill

The Horse Hill-1 well is located within onshore exploration license PEDL 137,
on the northern side of the Weald Basin near Gatwick Airport. Doriemus owns a
10% direct interest in Horse Hill Developments Ltd ("HHDL") HHDL is a special
purpose company that owns a 65% participating interest and operatorship of
licence PEDL 137 and the adjacent licence PEDL 246 in the UK Weald Basin. The
participants in the Horse Hill-1 well are HHDL with a 65% working interest and
Magellan Petroleum Corporation with a 35% interest. Dorimeus' net attributable
interest in PEDL 137 and 246 is therefore 6.5%.

Doriemus' Interest in Brockham

Doriemus holds a 10% interest in Brockham oil field (PL 235).

Qualified Person's Statement

The information contained in this announcement has been reviewed and approved
by Stephen Sanderson, Exploration and Technical Adviser to Doriemus, who has
over 33 years of relevant experience in the oil industry. Mr Sanderson is a
Fellow of the Geological Society of London and is an active member of the
American Association of Petroleum Geologists.

Glossary:

2D seismic           seismic data collected using the two-dimensional common
                     depth point method

argillaceous         a rock containing a significant proportion of clay
                     minerals

coccolithic          containing coccoliths which are the skeletal remains of
                     calcareous algae/plankton as found ubiquitously in the
                     Chalk of NW Europe

discovery            a discovery is a petroleum accumulation for which one or
                     several exploratory wells have established through
                     testing, sampling and/or logging the existence of a
                     significant quantity of potentially moveable hydrocarbons

electric logs        tools used within the wellbore to measure the rock and
                     fluid properties of surrounding rock formations

gamma-ray log        an electric log which measures natural background
                     radioactivity emitted mainly by potassium, uranium and
                     thorium isotopes used as a sedimentary lithology
                     discriminator

generative potential the amount of hydrocarbons that can be generated from a
(S2)                 unit volume of source rock established via the S2 peak
                     from rock-eval pyrolysis, normally expressed in
                     milligrammes of hydrocarbon per gramme of rock (or
                     kilogramme per tonne)

hot shale            a shale rock displaying average initial TOCs normally
                     exceeding 2% and represented by a high gamma ray electric
                     log reading

hydrogen index (HI)  the amount of hydrogen relative to the amount of organic
                     carbon in a sample, normally expressed in milligrammes of
                     hydrogen per gramme of TOC. The higher the amount of
                     hydrogen the more oil prone the source rock when subjected
                     to time temperature and pressure; an initial HI over 450
                     normally indicates an oil prone source rock

kerogen              the fraction of organic material in a sedimentary rocks
                     that is insoluble in the usual organic solvents being
                     composed of a variety of organic materials, including
                     algae, pollen, wood, vitrinite, and amorphous material.
                     Over time and subjected temperature and pressure kerogen
                     converts to hydrocarbons

micrite              a sedimentary rock formed of very fine grained calcareous
                     particles ranging in diameter from 0.06 to 2 mm, often
                     referred to as lime mudstone

mmbbls               millions of barrels

oil down to          the deepest level where oil saturation is measured at the
                     base of a porous reservoir where it directly overlies rock
                     of very low porosity and permeability where no reliable
                     oil water contact can be established

oil initially in     the quantity of oil or petroleum that is estimated to
place                exist originally in naturally occurring accumulations
                     before any extraction or production

oil saturation       the amount of the pore space within a reservoir containing
                     oil

oil water contact    a bounding surface in a reservoir above which
                     predominantly oil occurs and below which predominantly
                     water occurs.

P10                  a 10% probability that a stated volume will be equalled or
                     exceeded

P50                  a 50% probability that a stated volume will be equalled or
                     exceeded

P90                  a 90% probability that a stated volume will be equalled or
                     exceeded

play                 a set of known or postulated oil and or gas accumulations
                     sharing similar geologic, geographic, and temporal
                     properties, such as source rock, migration pathways,
                     timing, trapping mechanism, and hydrocarbon type

porosity             the percentage of void space in a rock formation, where
                     the void may contain, for example, water or petroleum

reservoir            a subsurface rock formation containing an individual
                     natural accumulation of moveable petroleum that is
                     confined by impermeable rock/formations

source rock          a rock rich in organic matter which, if subjected to
                     sufficient heat and pressure over geological time, will
                     generate oil or gas. Typical source rocks, usually shale
                     or limestone, contain above an initial 1% organic matter
                     by weight

spill point          the structurally lowest point in a hydrocarbon trap that
                     can retain hydrocarbons, normally coincides with a
                     hydrocarbon water contact

sweet spot           the area within a shale source rock unit showing highest
                     TOC and generative potential normally associated with
                     basin centred deposition

thermally mature     a term applied to source rocks which have received
                     sufficient temperature and pressure over geological time
                     to generate hydrocarbons

TOC                  total organic carbon - the weight percent amount of
                     organic carbon within the rock which is a commonly used
                     measure of hydrocarbon source rock richness

TVDss                true vertical depth below a subsea datum

vitrinite            a measure of the percentage of incident light reflected
reflectance (Ro)     from the surface of vitrinite particles in a sedimentary
                     rock. It is referred to as % Ro and is a measure of the
                     thermal maturity of a rock. Top of the oil window is
                     dependent on source rock type, but is widely recognized to
                     be at an Ro equivalent of between 0.5-0.7%

VSP                  vertical seismic profile, recording of seismic waves
                     directly at the borehole to enable seismic two way travel
                     time reflectors to be accurately correlated with formation
                     depths encountered by the well

Enquiries:

Doriemus plc                           +44 (0) 20 7440 0640
Donald Strang/Hamish Harris

Cairn Financial Advisers LLP           +44 (0) 20 7148 7900
Nominated Adviser and Broker
James Caithie/Jo Turner/Carolyn Sansom

Public Relations                       +44 (0) 20 7929 5599
Square 1 Consulting Ltd
David Bick/Mark Longson

A copy of this announcement is available from the Company's website at
www.doriemus.co.uk

                                    -ENDS-