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Horse Hill-1 Oil Discovery,
Aggregate Flow Rate Likely the Highest of any
Flow Test Highlights
· The final Portland test of 323 bopd, over an 8.5-hour, period is the highest stable dry oil flow rate from any onshore
· Proof that the Kimmeridge limestones contain significant volumes of moveable light oil that can be flowed to surface at commercial rates
· As previously reported, the stable, natural dry-oil flow rate of 464 bopd from the Lower Kimmeridge Limestone is the first ever flow from this rock unit in the
· Based on the analysis of published reports from all significant
· Based on the analysis of published reports from all significant
· High quality Brent Crude produced: light, sweet oil (40 degrees API in Kimmeridge, 35-37 degrees API in Portland) 1,940 barrels delivered to the
· Preliminary analysis confirms that the Lower and Upper Kimmeridge Limestone units are naturally fractured reservoirs with high deliverability
· Strong possibility for further optimisation and increased flow rates from all 3 zones in future development and production wells, particularly through the use of horizontal wells
Summary Table of Test Results
Zone |
Maximum Instantaneous Oil Rate |
Stabilised Dry Oil Rate |
Perforated Interval |
Stabilised Flow Period |
Depth Below Surface |
|
bopd |
bopd |
ft |
hours |
ft |
U. Portland * |
360 |
323 |
103 |
8.5 |
2000 |
U. Kimmeridge ** |
1008 |
901 |
88 |
4.0 |
2800 |
L. Kimmeridge ** |
700 |
464 |
80 |
7.5 |
2950 |
Total |
2068 |
1688 |
271 |
20 |
|
Note: * flow rate limited by pump stroke rate capacity ** natural flow |
Final Portland Flow Test
As previously reported, the first Portland test period gave a stable dry oil rate of 168 bopd over 9 hours. Further periods of flow using the same pump, re-seated immediately above the perforated zone, resulted in a similar stable dry oil flow over a two-day period. It was apparent that the rate was limited by the 7-ft stroke capacity of the pump. A larger 26-ft stroke pump was installed resulting in a maximum rate in excess of 360 bopd and an average stable rate of 323 bopd over 8.5 hours. This flow rate was still limited by pump capacity. During pumping, annulus fluid levels did not drop appreciably, implying little pressure depletion.
HH-1 Overview and Recap
The HH-1 discovery well, completed in
The analysis of thermal maturity data (vitrinite reflectance) from geological samples, by a leading analyst in
As previously announced, geochemical analysis of samples throughout the c. 1300 ft thick Kimmeridge shale section of HH-1, showed that the shales comprised a world class oil source rock. Analysis of 277 samples showed 780 ft of drilled section exceeding 2% total organic carbon ("TOC") by weight, with an average of 4.1% TOC. The richest section, and possible sweet-spot, lay between the Upper and Lower Kimmeridge Limestones with an average of 5% TOC and a high of 9.4% TOC. The organic shales demonstrated high oil generative potentials ranging from an average of 35 kg/tonne to a high of 103 kg/tonne and with high Hydrogen Indices ("HI") averaging 754. Further significant potential source rock sections were identified in the Middle Jurassic and Lias sections of the well.
Both Nutech and Schlumberger, leaders in the field of electric log analysis in rocks with low permeabilities, were then engaged to investigate the presence of oil in the HH-1 well. The Company reported the results during 2015, which indicated that a mean estimated total of between 9.97 and 10.99 billion barrels of OIP, or oil in the ground, existed under the HH-1 licence area, contained in shales and limestones of the Kimmeridge, Oxford Clay and Lias.
"The results to date are extremely encouraging and the company is now in a good position to make further opportunistic investments in the near term to create shareholder value"
Interest in Horse Hill
Qualified Person's Statement:
For further information please contact:
Hamish Harris
Nominated Adviser and Broker: +44 (0) 20 7148 7900
Cairn Financial Advisers LLP
James Caithie / Liam Murray
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 |
degree API |
a measure of the density of crude oil, as defined by the |
electric logs |
tools used within the wellbore to measure the rock and fluid properties of surrounding rock formations |
extended flow test |
a flow test, as per the permission granted by the |
flow test |
a flow test or well test involves testing a well by flowing hydrocarbons to 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 |
generative potential (S2) |
the amount of hydrocarbons that can be generated from a unit volume of source rock established via the S2 peak from rock-eval pyrolysis, normally expressed in milligrams of hydrocarbon per gram of rock (or kilogram per tonne) |
horizontal wells |
wells that during drilling are steered so as to be at or close to 90 degrees from the vertical to follow a particular geological stratum or reservoir unit |
hydrogen index (HI) |
the amount of hydrogen relative to the amount of organic carbon in a sample, normally expressed in milligrams of hydrogen per gram 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 |
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 |
magnetic resonance |
a phenomenon by which a nucleus absorbs electromagnetic radiation of a specific frequency in the presence of a strong magnetic field; it is used in modern electric logs |
mean |
or expected value, is the probability-weighted average of all possible values and is a measure of the central tendency either of a probability distribution or of the random variable characterised by that distribution |
moveable oil |
oil that can flow or be pumped to the surface |
naturally fractured reservoirs |
fractured reservoirs contain cracks or surface of breakage within rock; fractures can enhance permeability of rocks greatly by connecting pores together; naturally fractured reservoirs have been created over geological time by nature, not man-made via hydraulic fracturing |
organic rich |
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 2% organic matter by weight |
P50 |
a 50% probability that a stated volume will be equalled or exceeded |
peak oil generative window |
a vitrinite reflectance (Ro) measurement of 0.5-0.7%, indicating conditions that are thermally mature to generate moveable oil |
permeability |
the capability of a porous rock or sediment to permit the flow of fluids through its pore spaces |
pump stroke capacity |
in a rod pump the product of the rod cross-sectional area, maximum distance between the top and bottom of the rod stroke movement and the pump stroking speed |
recoverable volumes |
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 |
reservoir deliverability |
the fluid production rate that can be achieved from a particular reservoir or reservoir unit |
reservoir pressure depletion |
a reduction in reservoir pressure as indicated by downhole pressure gauges positioned in the well close to the zone being tested |
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 |
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 |
thermal maturity |
a term applied to source rocks which have received sufficient temperature and pressure over geological time to generate hydrocarbons |
total organic carbon |
the weight percentage of organic carbon within the rock which is a commonly used measure of hydrocarbon source rock richness |
vitrinite reflectance |
a measure of the percentage of incident light reflected 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 recognised to be at an Ro equivalent of between 0.5-0.7%. |
wildcat |
an exploration well in an unproven geological concept, rock unit or area |
This information is provided by RNS