The well, off England’s south coast, found oil in a separate reservoir from the well’s target which was not encountered because the well unexpectedly remained on the southern side of a bounding fault.
Drilling will now continue, with a side-track aimed at the primary target expected to take around two weeks to complete.
In this morning’s statement, United revealed that the Colter well encountered oil and gas shows over a 9.4-metre interval at the top of the Sherwood Sandstone reservoir, and, 3 metres of net pay was measured.
"Initial results from Colter have delivered a bonus in the form of an additional hydrocarbon structure, which has excellent initial oil and gas shows,” said Brian Larkin, United chief executive.
“This offers an pportunity for future appraisal and to increase the overall value of the Colter licence for our shareholders.
“More work will be required to determine the resource potential within the structure, and we will update shareholders on the outcome of the side-track well in the coming weeks."
United shares gained 0.2p or 5% to trade at 4.3p in Monday’s early deals.