An exploration well is due to be drilled at the Total-operated Isabella well later this month.
Israel-based Delek Group, owner of Ithaca Energy, has given an update on the “trial well”.
Isabella is targeting two prospects – the Joanne Sand and the Judy Sand – with a combined 63.4million barrels of oil and 499.2billion cubic feet of gas, according to best estimates.
Joanne, which holds the largest chunk, has a 42% chance of geological success while the secondary target Judy has 18%.
According to Delek, Ithaca is not covering any costs of drilling but will be entitled to 10% of any future revenues under a partnership agreement.
The overall cost is estimated to be £51m, Delek said, with any further production tests once the results are known to be £18m.
Operator Total holds a 30% stake in the project, while Neptune Energy has a 50% interest. The remainder is split between Ithaca and Edison Euro Oil Exploration, which was bought in July by Energean.
The well is located in the Central North Sea, around 170miles off the UK coast.