Cairn Energy announced that, although it encountered no hydrocarbons in arctic waters off Greenland\'s coast, it remained optimistic for the year. After leaving the coast of Greenland empty-handed in 2010, Cairn announced in January that it was returning to drill four exploration wells this year. The government of Greenland approved seven potential exploration drill sites for Cairn. Cairn said its four-well campaign for 2011 targets various structures in Greenland that have a mean prospective resource potential of 3.2 million barrels of oil equivalent. The company during its latest drilling campaign said, however, that it encountered no reserves in the LF7-1 well, the first basin it explored. \"The exploration challenge remains to find the reservoir sands,\" Cairn Chief Executive Officer Simon Thomson said in a statement. \"We continue to be optimistic about the remainder of our 2011 four-well, multi-basin exploration program offshore Greenland.\" Cairn early this year sued environmental group Greenpeace for harassment of its drilling campaign off the Greenland coast. Greenpeace said it was concerned about what would happen in the rough arctic waters in the event of an oil spill. \"Cairn\'s latest setback in Greenland is further evidence that chasing oil in the frozen north is a bad idea,\" Greenpeace said in a statement.