UK Oil & Gas Investments PLC

("UKOG" or the "Company")

Upgrade to Portland Oil in Place, Horse Hill-1 Discovery, Weald Basin

UK Oil & Gas Investments PLC (LSE AIM/ISDX: UKOG) announces that a new petrophysical analysis by Nutech, incorporating the findings of the successful Horse Hill-1 ("HH-1") flow test, demonstrates a threefold increase in calculated total oil in place (OIP) per square mile at the HH-1 well within the Upper Portland pay zone. As reported in May 2015 a total Horse Hill Portland P50 OIP of 21 million barrels ("MMbbl") was calculated utilising Nutech's petrophysical analyses. Nutech's May 2015 evaluation assigned a Portland OIP value of 7.7 MMbbl per square mile at the HH-1 well. Nutech's current evaluation upgrades the Portland OIP at HH-1 to 22.9 MMbbl per square mile, a 200% increase

As previously announced the final HH-1 Portland test flowed at a constrained stable dry oil rate of 323 barrels of oil per day ("bopd"). The Portland was produced at maximum pump capacity and showed no clear indication of depletion. It is likely that the rate can be further increased using a higher capacity downhole pump during the next planned test.

As previously stated by the Company, the calculated OIP per square mile should not be construed as recoverable resources, contingent or prospective resources or reserves.

HH-1 Discovery Well Location and Company Interest

The HH-1 well is located within onshore exploration Licence PEDL137, on the northern side of the Weald Basin near Gatwick Airport. PEDL246 lies adjacent to and immediately to the east of PEDL137 ("the Licences"). UKOG owns a 27.3% interest in the Licences, which are operated by Horse Hill Developments Ltd.

Background

Nutech's Report ("Report") details that the production of dry oil from the Portland, with little or no observed water production, required a rethink of the pre-flow test petrophysical model. Prior to the flow test, interpretations suggested that water would likely be produced along with oil, as is seen in Portland reservoirs in nearby producing oil fields. The revised model fully incorporates well test observations and measurements.

From a similar review of the petrophysical response within the Kimmeridge Limestones, the Report concludes that the well test results reinforce Nutech's and the Company's expectations regarding the significant volumes of OIP seen at the HH-1 well. As previously reported in April and June 2015, the overall Kimmeridge and Jurassic shale and limestone sequence is calculated to contain an OIP of 158 MMbbl per square mile at the HH-1 well and P50 9,245 MMbbl over the 55 square miles of the Licences.

Horse Hill Future Plans

The revised petrophysical model will be used to update Xodus' 2015 estimates of the total OIP contained within the mapped Horse Hill Portland oil accumulation. This will include an estimate of Contingent Resources net to the Company and will be reported in due course.

The Operator has also informed the Company that the flow test data analysis undertaken by Nutech and Xodus provides the necessary technical encouragement to engage Barton Wilmore Ltd, one of the UK's leading planning and environmental assessment practitioners, to prepare and submit a planning application to Surrey County Council ("SCC"), and to assist with obtaining necessary permissions from the Environment Agency ("EA"), for a significant appraisal programme at Horse Hill.

The applications will seek permission to conduct a programme consisting of the production flow testing of 3 Kimmeridge Limestone zones plus the overlying Portland over a total flow period of up to 360 days, plus two further appraisal/development wells and the acquisition of 3D seismic data.

A public consultation and engagement process related to the planning application is scheduled to take place, leading to an application to SCC and the EA.

Engineering studies to examine the range of possible flow rates from a planned horizontal sidetrack well are ongoing. Data to further calibrate these studies will be acquired during the further planned extended flow tests.

Stephen Sanderson, UKOG's Executive Chairman, commented:

"The record breaking flow test results and revised Nutech analysis gives us key new technical insight into the oil bearing Portland reservoir. More importantly than the simple increase in Portland oil in the ground, these learnings have significant positive implications for potential recovery factors and for future commercial viability. The economic potential of the Portland looks increasingly positive.

The validation of Nutech's Kimmeridge evaluation by the flow tests also underscore the Company's expectation that significant volumes of oil lie in the ground within the licence and can be brought to the surface at commercial rates.

We will work closely with Barton Willmore and others to ensure the necessary applications for regulatory consents are submitted. The granting of these permissions is the next key step to enable us to move the Horse Hill Portland and Kimmeridge projects forwards towards early monetisation.

We look forward to the conclusion of the regulatory consent cycle and eagerly await the start of planned long term flow testing."

Qualified Person's Statement:

Stephen Sanderson, UKOG's Executive Chairman, who has over 35 years of relevant experience in the oil industry, has approved the information contained in this announcement. Mr Sanderson is a Fellow of the Geological Society of London and is an active member of the American Association of Petroleum Geologists.

For further information, please contact:

UK Oil & Gas Investments PLC

Stephen Sanderson / Jason Berry Tel: 020 7440 0640

WH Ireland (Nominated Adviser and Broker)

James Joyce / James Bavister Tel: 020 7220 1666

Square 1 Consulting (Public Relations)

David Bick / Brian Alexander Tel: 020 7929 5599

Glossary:

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
contingent resources	contingent resources are 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. Contingent Resources are further categorized in accordance with the level of certainty associated with the estimates and may be sub-classified based on project maturity and/or characterized by their economic status
flow test	a flow test or well test involves testing a well by flowing hydrocarbons to the surface, typically through a test separator. Key measured parameters are oil and gas flow rates, downhole pressure and surface pressure. The overall objective is to identify the well's capacity to produce hydrocarbons at a commercial flow rate
horizontal well	the study of physical and chemical rock properties and their interactions with fluids utilising electric logs, physical rock and fluid measurements
limestone	a sedimentary rock predominantly composed of calcite (a crystalline mineral form of calcium carbonate) 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. The Kimmeridge Limestones are effectively chalks being comprised of the remains of calcareous planktonic algae
oil field	an accumulation, pool or group of pools of oil in the subsurface. An oil field consists of a reservoir in a shape that will trap hydrocarbons and that is covered by an impermeable or sealing rock
oil in place	the quantity of oil or petroleum that is estimated to exist originally in naturally occurring accumulations before any extraction or production
pay	the zone within a reservoir that contains economically recoverable hydrocarbons
petrophysics	the study of physical and chemical rock properties and their interactions with fluids utilising electric logs, physical rock and fluid measurements
P50	a 50% probability that a stated volume will be equalled or exceeded
reserves	those quantities of petroleum anticipated to be commercially recoverable by application of development projects to known accumulations from a given date forward under defined conditions; reserves must further satisfy four criteria: they must be discovered, recoverable, commercial and remaining (as of the evaluation date) based on the development project(s) applied; reserves are further categorized in accordance with the level of certainty associated with the estimates and may be sub-classified based on project maturity and/or characterised by development and production status

Notes to Editors:

About Barton Willmore

Barton Willmore is one the UK's largest planning practices, specialising in the planning, design and environmental assessment of energy projects from eleven regional oﬃces. Barton Willmore and their energy projects can be found be found on their website: www.bartonwillmore.co.uk/energy/

The Company has interests in the following UK licences:

Asset	Licence	UKOG's Interest	Licence Holder	Operator	Area (km²)	Status
Avington ¹	PEDL070	5%	UKOG (GB) Limited	IGas Energy Plc	18.3	Field in stable production.
Baxters Copse ²	PEDL233	50%	UKOG Weald Limited	IGas Energy Plc	89.6	Reviewing economics of appraisal/ development well.
Broadford Bridge	PEDL234	100%	Kimmeridge Oil and Gas Limited	Kimmeridge Oil and Gas Limited	300.0	BB-1 well permitted expected 2017 spud date.
Brockham ¹	PL235	3.6%	Angus Energy ⁵	Angus Energy ⁵	8.9	Drilling of sidetrack well being considered.
Holmwood ³	PEDL143	30%	UKOG	Europa Oil & Gas (Holdings) plc	91.8	H-1 exploration commitment well planned.
Horndean ¹	PL211	10%	UKOG (GB) Limited	IGas Energy Plc	27.3	Field in stable production.
Horse Hill ⁴	PEDL137	27.3%	Horse Hill Developments Ltd ⁶	Horse Hill Developments Ltd ⁶	99.3	Extended flow testing of HH-1.
Horse Hill ⁴	PEDL246	27.3%	Horse Hill Developments Ltd ⁶	Horse Hill Developments Ltd ⁶	43.6	Extended flow testing of HH-1.
Isle of Wight (Offshore) ³	P1916	100%	UKOG Solent Limited	UKOG Solent Limited	46.7	Preparing drilling planning submission.
Isle of Wight (Onshore) ^{2, 3}	PEDL331	65%	UKOG	TBA	200.0	Preparing drilling planning submission.
Lidsey ¹	PL241	4.2%	Angus Energy ⁵	Angus Energy ⁵	5.3	Drilling of infill well being considered.
Markwells Wood ²	PEDL126	100%	UKOG (GB) Limited	UKOG (GB) Limited	11.2	Compiling Field Development Plan.

Notes:

1. Oil field currently in production.

2. Oil discovery pending development and/or appraisal drilling.

3. Exploration asset with drillable prospects and leads.

4. Oil discovery with recently completed flow testing.

5. UKOG has a 6% interest in Angus Energy, which has a 70% interest in Lidsey and a 60% interest in Brockham.

6. UKOG has a direct 42% interest in HHDL, which has a 65% interest in PEDL137 and PEDL246.