Ensco, through its subsidiary, has finalised a shipyard construction contract with Keppel FELS in Singapore for the construction of two new ultra-premium harsh environment jack-up rigs.

The cost of construction, including commissioning, system integrated-testing and project management, is estimated at $230m per rig.

The two rigs are scheduled for delivery in the second and fourth quarters of 2013.

Ensco said the shipyard construction contract also includes options for two additional jack-ups of the same design at similar terms. These options are expected to be exercised in August 2011.

The rigs offer increased drilling efficiencies for large multi-well platform programmes, ultra-deep gas programmes or ultra-long reach wells up to 40,000ft in total drilling depth in oil and gas regions throughout the world.