The group holds a 95% stake in blocks 15/18d and 15/19b, which include the Crown Discovery that was initially discovered by energy giant ConocoPhilips in 1998.
On completion of the sale, UOG will receive US$950,000 for the blocks while US$50,000 will be paid to minority shareholder and partner, Swift Exploration Ltd.
An additional amount of up to US$3mln will be paid before the end of 2020, depending on certain milestones being achieved.
The deal is subject to completion of due diligence, regulatory approval and definitive documentation, UOG said.
"Our primary goal as a management team is to deliver value for our shareholders,” UOG chief executive Brian Larkin said.
“The work of our technical team in attaining and developing this licence has delivered an excellent outcome for the company, allowing us, on completion, to realise a significant return in a very short space of time.
“Our strategy involves the active management of our portfolio of assets, and this transaction demonstrates our ability to deliver on that strategy.”
Last month UOG announced that it has landed four new licences in the central North Sea via the UK’s 31st offshore licensing round.
It said it has been awarded a total of 500 square kilometres across the four blocks, positioned in a “highly prospective” area close to the Marigold and Yeoman discoveries, and, the Piper, MacCulloch and Claymore oil fields.