Drilling has now begun at the Serenity appraisal well in the central North Sea, after the Stena Don arrived on station earlier this week.
The start-up of drilling was confirmed by both firms in an announcement early Thursday morning.
The drilling programme is expected to last approximately 30 days, and will be plugged and abandoned after the completion of all drilling operations.
Petrofac will take on the task of well engineering operator, having secured a contract in May.
London and Toronto-listed i3 is hoping for 100 million recoverable barrels from the oil project.
Chief executive CEO Majid Shafiq has described the well as a “company-maker” and the “gem” in Aberdeenshire-headquartered firm’s portfolio.
i3 owns a 75% operated interest in the field following a recent 25% farm-out to Europa, in exchange for Europa funding 46.25% of the cost to a gross cap of £15 million.
Costs incurred above the £15m threshold will be funded in proportion to the respective working interest of each company.
Last year Mr Shafiq suggested there were multiple potential export routes in the event of success, including the Bleo Holm floating production, storage and offloading vessel (FPSO), or the Captain field.
However, if resources are as strong as hoped, then i3 may opt for a standalone FPSO.