Total cost, estimated to be nearly $610m includes commissioning, spares and project management, is anticipated to be paid out of cash flow and available funds.
Like its previously announced sister drillships, the new unit will be dynamically-positioned, have a seven ram blow-out preventer, dual activity capability, five mud pumps and a maximum hook-load capacity of 1,250 tons.
The delivery of third ultra-deepwater drillship is scheduled for the second quarter of 2014.
The new unit will be designed for operations in up to 12,000ft of water.
Diamond Offshore provides contract drilling services to the energy industry and is engaged in deepwater drilling.
