Highlands Natural Resources has raised £2.0m, gross, through an offer via PrimaryBid of 16,666,667 new ordinary shares at 12p apiece.
It said the offer was conditional on shareholder approval at a general meeting which was expected to be held at 11.00 a.m. on 31 July.
Chairman and chief executive Robert Price said: "We are delighted with the level of support received from investors who subscribed via PrimaryBid.
"The fundraising allows us to commence drilling at East Denver, where success will be transformational for Highlands, marking our first oil and gas production."
PrimaryBid chief operating officer Dave Mutton said: "It's exciting for PrimaryBid to assist another main market listed company to fundraise via our network of retail investors, demonstrating that fair access to new share issues is not just relevant for investors in AIM but for the main market too."