Portland Oil Discovery, Horse Hill-1, Weald Basin

24 October 2014 Doriemus plc ("Doriemus" or "the Company") Portland Oil Discovery, Horse Hill-1, Weald Basin UK Doriemus today announces that, following preliminary evaluation of the electriclogs, the Horse Hill-1 well has discovered an oil accumulation in theconventional Upper Jurassic Portland Sandstone at a top reservoir depth of1,791 feet TVDss. A preliminary most likely estimate of 3.1 million barrels ("mmbbls") of grossin place hydrocarbon volume has been calculated within the upper Portland, witha further gross unrisked in place prospective hydrocarbon volume of 16.8 mmbblsof oil in a separate lower sand in the Portland interval located in an untestedfault block to the south. As previously announced, the well is being deepenedto the Triassic where an additional target, believed to have potential for gas,is expected to be reached in the next two weeks. The Portland Sandstone was previously reported on 16 October 2014 to have oilshows in cuttings and elevated gas readings whilst drilling and theseindications have been confirmed by independent petrophysical analysis of theelectric logs acquired in the well during the last week. Further analysis iscontinuing to establish the recoverable volume of oil that has been discovered. Donald Strang, the Company's Chairman, commented: "We are delighted with the results so far from this well. The presence of alarger, unappraised, Portland feature creates considerable further upside. Weare now looking forward to drilling the Triassic, which is a new and untestedexploration target in the area and which, if successful, may containappreciable volumes of gas." The Horse Hill-1 well is located on the northern side of the Weald Basin nearGatwick Airport. Doriemus owns a 10% interest in Horse Hill Development Limited("HHDL"), a special purpose company. HHDL owns a 65% participating interest andis the operator of onshore licences PEDL 137 and the adjacent licence PEDL 246in the Weald Basin. The participants in the Horse Hill-1 well are HHDL with a65% working interest and Magellan Petroleum Corporation with a 35% interest.Doriemus's net interest in any discovery is 6.5%. Additional analysis: The upper Portland Sandstone reservoir, which produces at the nearby Brockhamoil field, was also intersected by the Collendean Farm-1 explorationapproximately 790 metres north of the Horse Hill-1 well. Using the solelyavailable 2D seismic data and the well results, the operator has mapped an areaof closure of approximately 3.8 square kilometres where the Portland Sandstoneis above the observed oil down to at a depth of 1,901 feet TVDss. The presenceof two wells within the same mapped structural closure significantly increasesthe confidence in a commercial discovery and there is every indication that thePortland reservoir can be developed as a commercial oil field. The gross oil bearing upper Portland Sandstone interval in Horse Hill-1measures 102 feet, has an average porosity of over 16% and average oilsaturation is estimated as 36%. Based on regional and local trends, confirmedby wells at Brockham, these reservoir parameters indicate a high likelihood ofproduction at commercial rates. The equivalent interval in the CollendeanFarm-1 well, drilled by Esso in 1964, shows similar reservoir characteristicsover a 97 foot gross interval. The gross oil column contained within the HorseHill-Collendean Farm structure is in excess of 140 feet. The lower Portland Sandstone reservoir, which is seen to be water wet in HorseHill-1 and Collendean Farm-1, lies above the oil down to in an untested faultblock to the south of the Horse Hill-1 well and is interpreted to contain aprospective most likely in place oil gross volume of 16.8 mmbbls. The Corallian Sandstone and Great Oolite targets in the Horse Hill-1 well arenot seen on electric logging to contain moveable hydrocarbons, however, furtherevaluation of several thick Kimmeridgian-age limestones, which had hydrocarbonshows and elevated mud gas readings whilst drilling, may provide additional oilpotential within the well. Low, medium and high estimates of Portland oil in place are summarised in Table1. Table 1: Estimated gross in place discovered and undiscovered oil volumes mmbbls, Low (P90) Medium (P50) High (P10)in-place-oil Discovered 1.5 3.1 4.8 Undiscovered 7.8 16.8 29.7 The gross in place hydrocarbon volumes have been prepared by Stephen Sandersonacting as the competent person on behalf of HHDL. Volumes have been prepared using the methodologies and standards published bythe Society of Petroleum Engineers. The gross in place hydrocarbon volumes presented should not be considered aseither contingent resources or reserves. Competent Person's Statement: The technical information contained in this announcement has, for the purposesof the AIM Guidance Note for Mining, Oil and Gas companies has been reviewedand approved by Jonathan Tidswell-Pretorius, executive director at HHDL andChairman of Angus Energy Ltd, a UK-registered onshore operator who has 15 yearsof relevant experience in the oil and gas industry. Mr. Tidswell-Pretorius isa member of the Society of Petroleum Engineers and United Kingdom Onshore Oiland Gas (UKOOG) industry bodies. Glossary: 2D seismic seismic data collected using the two-dimensional common depth point method contingent resources those quantities of petroleum estimated, as of a given date, to be potentially recoverable from known accumulations, but the applied project(s) are not yet considered mature enough for commercial development due to one or more contingencies. Contingent Resources may include, for example, projects for which there are currently no viable markets, or where commercial recovery is dependent on technology under development, or where evaluation of the accumulation is insufficient to clearly assess commerciality discovered/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 mmbbls million 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 in place the quantity of oil or petroleum that is estimated to exist originally in naturally occurring accumulations before any extraction or production oil saturation the percentage of available pore space within the reservoir containing oil 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 porosity the percentage of void space in a rock formation, where the void may contain, for example, water or petroleum reserves those quantities of petroleum anticipated to be commercially recoverable by application of development projects to known accumulations at a given date forward under defined conditions TVDss true vertical depth below a subsea datum undiscovered those quantities of petroleum which are estimated, as of a given date, to be contained within accumulations that have not been tested by drilling Enquiries: Doriemus plc Donald Strang, Chairman +44 (0) 20 7440 0640 Cairn Financial Advisers LLP: James Caithie / Jo Turner / Carolyn Sansom +44 (0) 20 7148 7900