It is selling 1.32bn new shares priced at 0.17p each in a share placing arranged by broker SP Angel.
"The board is delighted with the result of the oversubscribed fundraising and, given current testing equity market conditions,” said David Bramhill, Union Jack executive chairman.
Bramhill added: "Given the successful West Newton A-2 appraisal well result, and our improved financial position resulting from this fundraising, we keenly await the results of the planned extended well test in the third quarter of 2019 that will be expanded to test the liquid and/or gas intervals evident in the well.
“If the planned extended well test is successful, West Newton could be transformational for Union Jack and deliver growth in reserves, production and shareholder value.”
The funding comes after a statement released late on Thursday afternoon, relaying communications from operator Rathlin Energy to residents in the vicinity of the well site.
It confirmed the well testing, planning permissions and the pending well test programme.
"The directors are extremely confident about the future prospects for Union Jack and look forward to updating the market on developments at the West Newton production test and its wider portfolio,” Bramhill added, this morning.