Cairn Energy, the Scotland-based oil and gas exploration group, on Tuesday started the construction of a pipeline from its fields in Rajasthan's Barmer district to a coastal location in Jamnagar district of Gujarat. The 600 km pipeline will be used for sending of heated crude oil to refinery in Gujarat. But with the company still unable to sign a deal with any refiner, it still has to cross some hurdles before it can laugh all the way to the bank.