The operator is aiming to confirm estimates that the prospect, around 40 miles from the Yorkshire coast, holds between 220 to 300 billion cubic feet of gas.
The Ensco 123 rig was contracted to drill the appraisal well which spudded on Thursday, August 8, according to information on the Oil and Gas Authority website.
He has also vowed to review the 107 contracts already awarded to companies through auctions over the last few years to check for corruption, although he has said he would not try to invalidate them so long as they check out.