Not so long ago, advanced drillships costing more than half a billion dollars each and capable of operating in ever-deeper waters practically guaranteed big profits for oil-rig operators. Now, with oil prices down by half since June, many have become a burden on their owners as drilling activity slows. Drillship operators face a more brutal hit to margins than they did after the oil-price crash of 2008 because of the huge cost of maintaining the more than $10 billion worth of state-of-the-art vessels that have been idled at sea, analysts say. Noble Corp Plc, Ensco Plc and Transocean Ltd are among companies that have invested in advanced rigs which, unlike older jack-up rigs that attach to the ocean floor, rely on dynamic positioning systems using thrusters to keep them in position. And it’s these thrusters that are the problem. They need to be removed to […]