Transocean has approached Daewoo Shipbuilding & Marine Engineering (DSME) to build its seventh drillship on the back of a firm five-year charter contract with oil major Chevron.

Transocean, provider of offshore contract drilling services for oil and gas wells, said the contract with Chevron is expected to contribute about $1.1bn in revenue, while the investment for the newbuild drillship is estimated at $725m.

Construction of the ultra-deepwater drillship is scheduled to commence during the fourth quarter of 2014 at DSME, and Transocean's charter deal with Chevron will begin in the fourth quarter of 2016.

The drillship is designed and outfitted to operate in water depths of up to 12,000 feet and drill wells to 40,000 feet.

Transocean already has five rigs built at DSME's Okpo facility and a sixth is currently under construction.

Meanwhile, South Korea's DSME announced yesterday it won an order to build two new drillships worth $1.24bn for an unnamed Africa-based company.