A total of 2,500 feet was successfully drilled horizontally wholly within the targeted ‘sweet spot’ of the conventional Portland oil reservoir.
It was decided, according to Alba, that there was little technical or economic merit in completed the maximum allowed horizontal section, of 3,000 feet, because the programme achieved a good, clean horizontal trajectory.
The new horizontal well (HH-2z) is now being prepared for extensive well testing, due to start in the coming weeks, ahead of a transition into long term production.
It is anticipated that the well test will include the use of a downhole electric pump over a 90-day period.
In the meantime, test production separately continues for the HH-1 well which has to date flowed in excess of 77,200 barrels of crude oil.
"We are pleased to be able to report on the successful completion of this drilling campaign at the Horse Hill Oil Field,” Frangeskides said.
Alba holds an 11.765% interest in the vehicle Horse Hill Developments Limited (HHDL) which in turn owns 65% of the project.
UKOG chief executive Stephen Sanderson, in a separate statement, said: "We are delighted to have safely and successfully delivered a significant 2,500 ft of horizontal section within the Portland reservoir's sweet-spot, the prime 35 ft zone containing the reservoir's most oil productive sandstones.
“The significant horizontal trajectory, combined with the continued positive indications of increased reservoir quality and lower pressure-depletion, effectively negated any technical or economic need to attain the maximum planned c. 3,000 ft horizontal section. As a result, HH-2z remains optimally placed to be able to deliver its goal of significantly higher flow rates than the highly productive HH-1 vertical discovery."
He added: “We now look forward to the imminent flow test campaign, a key step towards delivering significant long-term production at Horse Hill."