Oslo and New York-listed rig owner Seadrill announced that it has placed an order for two tender rigs at COSCO Nantong Shipyard in China with delivery expected in the first and third quarter of 2013, respectively.

Total project price is estimated at $225 million, which includes project management, drilling and handling tools, spares and capitalized interest.

"The two new units will be based on similar design and specifications as recently built tender rigs, but with enhanced drilling capabilities allowing for higher drilling efficiency including the advantage of a light weight drilling equipment set," the Bermuda-based company wrote in an exchange filing.

Seadrill says the units have been chartered to Chevron Thailand Exploration and Production in a $420m contract running five years.

Seadrill Management CEO Alf C Thorkildsen says: "These newbuilds are an important addition to our present tender rig fleet. The new orders increase earnings and visibility, and enhance the attractiveness of our fleet. The $420 million of new contracts demonstrates the competitiveness of our tender rig concept. T15 and T16 will be added to a fleet of four tender rigs already operating for Chevron, further strengthening our relationship with a leading global client."