Ineos boss Jim Ratcliffe is reported to have made a takeover approach to ConocoPhillips for its North Sea assets which was rejected by the company.
According to reports in the Sunday Times, the $2billion plus offer was turned down amid a boardroom shake-up.
ConocoPhillips has been operating in Britain for more than 50 years and employs around 900 people.
Ineos is said to have tried to purchase the British arm of the US oil and gas firm.
According to sources, private equity firm Blackstone is also said to have made a bid.
It comes after Ineos spent £500million buying a dozen gas fields from LetterOne.