Oil explorer Cairn Energy has secured a second drilling rig to assist its exploration programme in the Disko West area offshore Greenland in the second half of 2010.The rig, the Stena Don, will work alongside the Stena Forth, and help increase Cairn's operational flexibility and capability in its exploration activities.Cairn announced that it had secured Stena Forth, allowing it to start exploration ahead of schedule, on December 21.'Contracting a second drilling rig for Greenland has further increased Cairn's operational capability and flexibility,' said Cairn deputy chief executive Mike Watts.'We can now look forward to drilling up to four exploration wells in the undrilled Baffin Bay Basin offshore Disko West later this year.'