11 May 2015



                                 Doriemus plc

                         ("Doriemus" or the "Company")

  Upgrade to Horse Hill Conventional Portland Sandstone Oil in Place Volumes


Doriemus plc (LSE AIM: DOR) is pleased to announce an upgrade to the
conventional Stock Tank Oil Initially In Place ("STOIIP") volumes estimated for
the overall Upper Portland Sandstone conventional reservoir in the Horse Hill-1
("HH-1") and Collendean Farm-1 ("CF-1") structure (`Horse Hill'), in the
PEDL137 licence area (Surrey-West Sussex, Weald Basin). This revised STOIIP is
separate to the oil-in-place volumes estimated for the argillaceous limestones
and mudstones of the Kimmeridge, Oxford and Lias rock sections of the HH-1
well, as reported on 9 April2015 and 15 April 2015. The Company has a net
attributable interest of 6.5% in PEDL137.

An independent study of the Portland Sandstone reservoir was conducted by Xodus
Group ("Xodus"), an international energy consultancy based in the UK (see
www.xodusgroup.com), for the Horse Hill Developments Ltd (HHDL) main consortium
partners UK Oil and Gas Investments PLC (UKOG). The study is based on new
petrophysical evaluations of both the HH-1 discovery and the older Collendean
Farm-1 ("CF-1") well plus an updated interpretation of 2D seismic data across
the Licence. The study report is available on UKOG's website (see
www.ukogplc.com).

The HH-1 and CF-1 discoveries lie within an approximately 100-foot thick, Upper
Portland Sandstone gross reservoir interval, within a 6km by 3km tilted fault
block structure as defined by 2D seismic. The crest of the Upper Portland
conventional oil discovery lies at approximately 1,760ft TVDSS, and extends
over a mapped maximum areal closure of approximately 2,000 acres. The Upper
Portland reservoir is productive at the nearby Brockham field, some 9km NNW, in
which UKOG has an indirect interest of 3.6%.

Xodus calculate that the Upper Portland Sandstone conventional reservoir
contains a "Best Estimate" (P50) gross STOIIP of 21.0 MMbbl, which is slightly
more than UKOG's own revised latest estimate of 20MMbbl, and which is entirely
within PEDL137 and encompasses both the HH-1 and CF-1 wells. This is an
increase of 12.8 MMbbl over the 8.2 MMbbl (P50) gross STOIIP reported on 17
December 2014, which results largely from the new petrophysical evaluation of
HH-1 electric logs, calibrated to new XRD and MICP data, and a new
interpretation of the CF-1 electric logs, calibrated to core data.

The gross Upper Portland STOIIP ranges estimated by Xodus are as per the table
below:

     STOIIP (MMbbl)           Low          Best         High         Mean

Upper Portland Gross 100%     14.3         21.0         30.4         21.8


The oil in place hydrocarbon volumes (STOIIP) estimated should not be construed
as recoverable resources or reserves. Meaningful estimates of recoverable oil
within the Upper Portland can likely only be made following the proposed HH-1
flow test and a significant proportion will not be recovered during any future
production regime

The Upper Portland is the uppermost, conventional oil-saturated reservoir found
in the HH-1 and CF-1 wells. It overlies, and is entirely separate from, the
Kimmeridge, Oxford and Lias oil-saturated argillaceous limestone and mudstone
rock sections reported on 9 April 2015 and 15 April 2015.

The Xodus study is an independent review, solely of the Upper Portland
Sandstone trap-constrained conventional oil reservoir. It does not include any
assessment of the deeper Kimmeridge, Oxford and Lias oil-saturated argillaceous
limestone and mudstone rock sections, which are currently the subject of a
separate review by Nutech Ltd.


Reporting Standards:

Xodus' STOIIP volumes have been prepared in accordance with the 2007 Petroleum
Resources Management System prepared by the Oil and Gas Reserves Committee of
the Society of Petroleum Engineers (SPE), reviewed, and jointly sponsored by
the World Petroleum Council (WPC), the American Association of Petroleum
Geologists (AAPG) and the Society of Petroleum Evaluation Engineers (SPEE).

Xodus state in their Executive Summary that; "In conducting this review Xodus
has utilised information and interpretations supplied by UKOG, comprising
operator information, geological, geophysical, petrophysical, well logs and
other data along with various technical reports. Xodus has reviewed the
information provided and modified assumptions where it considered this to be
appropriate. Site visits were not considered necessary for the purposes of this
report."


Donald Strang, Doriemus' Chairman, commented:

"The Xodus Report supports the Company's view that the Horse Hill and
Collendean Farm oil pool constitutes a significant conventional Upper Portland
Sandstone oil discovery in the Weald basin.

Subject to approval by the relevant authorities, the Consortium intends to flow
test this conventional sandstone zone as part of a wider test programme of the
HH-1 well later in 2015. A successful test would be followed by a full
technical resource assessment, and the identification of potentially
recoverable resource volumes.

Subject to these results, the Company is informed that the operator, Horse Hill
Developments Ltd, intends to engage with the Oil and Gas Authority ("OGA") and
other regulators, and seek to move the PEDL137 licence into the Production
Period as soon as practicable, via submission of a Field Development Plan to
the OGA. The PEDL137 licence is currently in the exploration phase and expires
on 30 September 2015. HHDL has applied for a one-year extension of the
exploration phase to 30 September 2016."


Doriemus' interest in Horse Hill:

The Horse Hill-1 well is located within onshore exploration License PEDL137, on
the northern side of the Weald Basin near Gatwick Airport. Doriemus owns a 10%
direct interest in Horse Hill Developments Ltd. HHDL is a special purpose
company that owns 65% participating interests and is the operator of licence
PEDL137 and the adjacent licence PEDL246 in the UK Weald Basin. The remaining
35% participating interests in the PEDL137 and PEDL246 licenses are held by
Magellan Petroleum Corporation.


For further information please contact:

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

Cairn Financial Advisers LLP:
James Caithie / Carolyn Sansom               +44 (0) 20 7148 7900

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


Glossary:

argillaceous         a limestone containing a significant proportion of clay
limestone            minerals

clastic              rocks composed of broken pieces of older rocks

Core                 a cylindrical sample of rock, obtained during drilling of
                     wells and removed for inspection at surface

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

fault block          a very large subsurface block of rock, created by tectonic
                     and localised stresses

limestone            a carbonate sedimentary rock predominantly composed of
                     calcite of organic, chemical or detrital origin. Minor
                     amounts of dolomite, chert and clay are common in
                     limestones. Chalk is a form of fine-grained limestone

MICP                 mercury injection capillary pressure, a measure of rock
                     porosity and permeability, from rock cores or cuttings,
                     and a calibration of porosity logs

MMbbl                Million barrels

mudstone             an extremely fine-grained sedimentary rock consisting of a
                     mixture of clay and silt-sized particles

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

petrophysical        the study of physical and chemical rock properties and
evaluation           their interactions with fluids; studies typically use well
                     logs, well cores and seismic data

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

recovery or          the quantity or portion of petroleum, here oil and gas,
recoverable          initially-in-place that can be extracted by a well or
                     wells to the surface

Resources            the Society of Petroleum engineers ("SPE") defines as all
                     quantities of petroleum, here oil and gas, which are
                     estimated to be initially-in-place; however, some users
                     consider only the estimated recoverable portion to
                     constitute a resource.

Reserves             reserves are defined by the SPE as those quantities of
                     petroleum, here oil and gas, which are anticipated to be
                     commercially recovered from known accumulations from a
                     given date forward.

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

sandstone            a clastic sedimentary rock whose grains are predominantly
                     sand-sized. The term is commonly used to imply
                     consolidated sand or a rock made of predominantly quartz
                     sand

Seismic              use of reflected and refracted sound waves generated at
                     the surface to ascertain the nature of the subsurface
                     geological structures. 2D seismic records a two
                     dimensional cross-section through the subsurface collected
                     using the two-dimensional common depth point method

STOIIP               stock tank oil initially in place

TVDSS                true vertical depth below a subsea datum

XRD                  x-ray diffraction; scattering of x-rays by the atoms of a
                     rock or crystal that gives information on the structure,
                     composition and identity of the rock or crystal