NORTH Sea-focused Hurricane Energy has started drilling a well on the Lancaster discovery West of Shetland which will help it decide if the find is big enough to be worth bringing into production. The Surrey-based firm thinks Lancaster may hold up to 456 million barrels oil equivalent. The crude price slump has made some firms reluctant to invest in exploration and development work. In June Hurricane suspended talks about selling a stake in Lancaster pending the results of this summer’s drilling campaign. It won £44m backing from the Kerogen private equity firm in April. Some investors believe deals cans be done at attractive valuations in the North Sea amid the downturn triggered by the crude price slump.