Shares in Angus Energy Plc (LON:ANGS) rose 10% after the company provided a positive update on its Brockham re-entry oil well, just down the road from Horse Hill, home of the Gatwick gusher.
The company said the Kimmeridge and other formations appear to be the same in structure to the oil-bearing Kimmeridge sections of the Horse Hill-1 well.
Notably, the Corallian formation, which lies immediately below the Kimmeridge, had both oil and gas shows, Angus added.
In drilling the side-track at Brockham, Angus first went into the Portland sandstone, host to a known oil play that is already generating 35 barrels a day.
It then pushed on into the Kimmeridge, before perforating the Coralian.
It was the Kimmeridge that set the gusher at Gatwick gushing at 1,688 barrels a day.
Three discrete layers within this horizon are of particular interest to the Angus team.
Over the last two to three decades around 30 wells have been drilled into the Kimmeridge limestones of the Weald Basin, which underlies the south and south-eastern corner of England.
However they were never tested for oil as the sedimentary rock was thought to lack the porosity required to host it.
What the experts suspect is the Kimmeridge at Horse Hill is naturally fractured, allowing oil to accumulate that when accessed flows easily to surface under its own steam.
If this model holds up then there would be no need for fracking to release this hydrocarbon bounty.
There is no guarantee that Brockham will enjoy identical geology to Horse Hill – but there is a suspicion it does; well more than that.
It is a hunch based on drilling carried out by BP, which used to own the Brockham licence.
One of Angus’ field partners, a firm called Doriemus, commissioned the consultant Nutech to make a comparative analysis of the Horse Hill-1 well and Brockham-1, sunk by BP in 1987.
It is too early to definitively assert this, but Angus believes the maturity and fracture analysis of the two have striking similarities.
Thursday’s update adds to the weight of evidence. However we won’t know definitively just what’s actually under Brockham until it is flow tested.
“We will update the market as soon as possible with the results of the further analysis and as we progress further down the path towards production,” said Angus chairman Jonathan Tidswell-Pretorius.
He added: "We are pleased to have encountered hydrocarbon shows missed in the previous drilling by BP in 1987 in the three Kimmeridge target intervals and are delighted to see encouragement for the predicted analogy to the Horse Hill geology.
“Encouragingly, we have also seen oil and gas shows in the underlying Corallian. Further analysis is underway to identify the extent of hydrocarbon presence and the ability of these hydrocarbons to freely move into the wellbore.
“New Ultra Wave well logging technology has been used in the logging of this well and will, once analysed, allow us to make an image of the borehole wall in order to map the presence of, and density of, natural fractures in the target reservoirs.
“This will enable us to target the most prospective zones which have the highest potential for future production."