UPDATE 1-Noble to buy two jackup rigs for $440 mln

* Contract with Singapores' Sembcorp Marine subsidiary

* Rigs to be delivered in Q4, 2012 and Q2, 2013

* Contract has options for up to 4 more rigs

Dec 21 (Reuters) - Noble Corp (NE.N) said a unit of Singapore's Sembcorp Marine (SCMN.SI) will build two jackup rigs for the world's No. 2 offshore drilling contractor by fleet size, for about $440 million.

The announcement by Noble, which owns 71 offshore rigs, and No. 1 rig contractor Transocean's (RIG.N) recent deal to buy a new jackup rig for $195 million reflect the growing demand for latest technology in shallow-water drilling.

Noble said the rigs, which will be able to operate in depths up to 400 feet and drill to depths of 30,000 feet, are to be delivered in the fourth quarter of 2012 and the second quarter of 2013.

The contract has options for up to four additional rigs, which must be exercised by Jan. 1, 2012.

Noble said 20 percent of the construction price is due at the signing, 20 percent due at steel cutting, and the rest at rig delivery.

Noble shares were trading flat at $34.78 on Tuesday morning on the New York Stock Exchange. (Reporting by Krishna N Das in Bangalore; Editing by Joyjeet Das)