LONDON (Reuters) - British oil and gas company Hurricane Energy started up its Lancaster field west of Scotland's Shetland Islands, it said on Monday, pushing its shares up 6 percent to a seven-week high.Hurricane specialises in recovering oil from fractures in hard and brittle rock known as fractured basement reservoirs, which some see as a risky way to obtain crude.Hurricane's floating production, storage and offloading (FPSO) vessel was connected to the group's North Sea Lancaster oilfield in..