Cairn Energy has received formal approval from the Government of Greenland to start drilling the first two wells of a planned four well exploration programme in the Disko West area, offshore Western Greenland.The Edinburgh-based oil company, which struck big in Rajasthan in the north west of India six years ago, has high hopes for its Greenland campaign.In 2007, Cairn signed licence agreements for two blocks off West Greenland (Sigguk and Eqqua) and farmed into two blocks operated by Canada's EnCana (Atammik and Lady Franklin). The following year, the London-listed firm was awarded a further four blocks in South Greenland (Kingittoq, Saqqamiut, Salliit and Uummannarsuaq), then, in 2009, it sold a 10% interest in its six operated blocks offshore Greenland to Malaysia's Petronas.The US Geological Survey (USGS) thinks prospects are good. "The extensive Arctic continental shelf may constitute the geographically largest unexplored prospective area for petroleum remaining on earth," it has said.