UK Oil and Gas (LON:UKOG) has received consent from the Environment Agency to carry out a flow test at the keenly watched Horse Hill-1 well near Gatwick.
The explorer created huge excitement in April, when it said the well, drilled into the Weald Basin under Dorset, Surrey and Sussex, had discovered more than a hundred billion barrels of oil.
This flow test will be the first stage of quantifying exactly how much oil the ‘Gatwick Gusher’ actually contains and how much is commercially recoverable.
HH1 was drilled on the northern side of the Weald Basin, three miles or so from the airport.
The flow test is designed to assess both the oil bearing Upper Portland sandstone reservoir and the Kimmeridge limestone reservoirs beneath the Portland.
UKOG will test the commercial viability of the shallow Portland sandstone, which is believed to contain around 20mln barrels of which a few million may be recoverable, while carrying out a ‘proof of concept’ for the potentially much more substantial Kimmeridge tight oil play.
Here, UKOG is hoping for confirmation of round one billion barrels oil in place from the 200 feet or so of limestone rocks, which may ultimately translate into between 30-50mln barrels net to the company.
Testing will start as soon as the remaining regulatory approvals from the Health and Safety Executive and Oil and Gas Authority come through and likely to be early 2016.
Stephen Sanderson, UKOG's executive chairman said: "The consent to flow test is a major milestone for the company.
The flow test's outcome will help UKOG shape its future Portland oil development activities and materially advance its knowledge and growth in the Kimmeridge tight oil play within our licences and the wider Weald Basin.
UKOG has a 31% stake in HHDL, the operating company that owns a a 65% stake in the licence.
Neil Ritson, chairman of Solo Oil (LON:SOLO), one of the other members of the HHDL consortium added the test would be important in assessing the viability of a Portland oil development. It would also provide additional data on the high potential Kimmeridge tight oil play, he said.
Solo owns a 10% direct interest in HHDL.