Tullow Oil shares have slid almost 10% after an update from its joint venture in French Guiana.
One of its partners Northern Petroleum announced that an exploration well on the Guyane Maritime permit would drill deeper after no hydrocarbons were found in the initial campaign.
The move to drill deeper is intended to give a better understanding of the potential of the area but will lead to a small delay to futher planned wells. Northern's managing director Derek Musgrove said:
Whilst the sand package in the primary target proved not to have significant hydrocarbons at this location, the oil staining encountered... is encouraging of the broader active hydrocarbon systems and potential.
But Tullow has fallen 105p to 975p on the news, the biggest loser in the FTSE 100. Northern is down 18% at 32p. The other partners are Shell and Total.
