Ophir Energy has taken a near $310 million impairment on its proposed Fortuna floating liquefied natural gas project off Equatorial Guinea but remains in talks with potential partners about rescuing the troublesome scheme before the imminent expiry of its licence.

The London-listed player, which is to shut its headquarters in the UK capital and set up shop instead in its new core area of Southeast Asia, chopped its valuation of the proposed Block R development to $300 million and admitted it could plunge to zero at the end of the year, when the production sharing contract expires.