Corallian Energy has raised almost £1 million to help pay for the Curlew-A appraisal well.
The Curlew-A discovery was made by Shell in 1977 in the prolific Central Graben area.
But Shell relinquished licence P2396, which contains Curlew-A, in 2016 and it was awarded to Corallian in the 30th bidding round.
It is thought to contain 45 million barrels of oil.
In October, UK firm Corallian agreed to sell 10% of the licence to Australia’s Talon Petroleum.
Talon said it would cover 15% of the cost of appraising Curlew-A up to a cap of £12 million.
The current estimated well cost, using a jack-up rig, is £9.7m.
Corallian, which plans to drill in the second half of 2019, has now raised £912,300 through an advanced subscription agreement.
London-based investor Reabold Resources, which owns 32.9% of Corallian, is participating in the fund raiser with an investment of £300,000.