MAERSK Drilling has declared its option to build two ultra-deepwater drillships at Samsung Heavy Industries in South Korea, at a cost of $1.3billion.
The units are scheduled for delivery during the second half of 2014.
At around the same time, Songa is due to receive its new category-D DSME rigs, also from South Korea.
Simultaneously, Maersk Drilling has obtained a new option for the construction of two further drillships, as it seeks to build its position on the global deepwater drilling stage in the face of stiff competition from the Americans.
Chief executive, Claus V. Hemmingsen, said: “We have an ambition of becoming one of the leading drilling contractors in the ultra-deepwater segment.
“This order is another important step in taking a bigger share of this attractive market segment.
“The order reflects our commitment to growing our rig fleet, enabling us to serve our customers in the ultra-deepwater segment on a more regular basis.”
In the year to date, Maersk Drilling has invested $3.8billion in two new jack-up rigs and four drillships.
Mr Hemmingsen has forecast a strong market for deepwater drilling rigs as the global demand for oil is increasing, while at the same time production from mature fields is declining.
“This means that about six times the current Saudi production must be brought onstream over the next 20-25 years, which will drive a solid growth in the demand for drilling services,” he added.
“The main part of this growth will take place in frontier areas such as deepwater.”
The latest pair of drillships ordered will be of a similar design to the two ordered from Samsung in April.
The 228m vessels will be able to operate at water depths to 3,650m (12,000ft) and be capable of drilling wells of more than 12,200m (40,000ft).
The drillship design includes a dual derrick to enable parallel and offline activities.
Extensive storage areas and tank capacities will allow such ships to operate for significant periods in areas with less developed infrastructure and limited presence of suppliers.