A novel well bore drilling system and method utilizes independently deployable multiple tubular strings to drill, line and cement multiple hole sections without intervening trips to the surface. In one embodiment, the drilling system includes two or more independent, telescoping, tubular members that...http://www.google.co.uk/patents/US7757784?utm_source=gb-gplus-sharePatent US7757784 - Drilling methods utilizing independently deployable multiple tubular strings
