Shares in Britain's Angus Energy jumped as much as 12 per cent as the market opened today after the firm announced drilling results at its Brockham well "could be even better" than that of the Gatwick Gusher.
Shares in the oil firm, which is listed on London's Alternative Investment Market (Aim), were up 6.12 per cent at 13p in late morning trading.
Based on preliminary results, Angus said it "has confidence the well will be similar to Horse Hill and perhaps given that the reservoir is potentially much thicker in zones not previously tested the results could be even better".
"These results achieve everything short of production to prove the potential from this zone," Angus said in its statement.
Horse Hill is the site of the so-called Gatwick Gusher wells, where discoveries were led by UK Oil and Gas Investments (Ukog). Studies have indicated that there are estimated reserves of around 10 billion barrels at the Horse Hill site near Gatwick Airport.
Last April, Ukog bought up Angus Energy's 7.8 per cent stake in the Weald Basin development area in a £1.8m cash and share deal, increasing its holding in Horse Hill from just under a fifth to just over a quarter.
Angus plans to bring the Surrey well's Kimmeridge shale into production at its existing Brockham production facility as soon as the necessary approvals by the Oil and Gas Authority are in place.