Singapore’s Keppel Offshore & Marine Ltd. has firmed up contracts with Sete Brasil for the design and construction of five additional semisubmersible drilling rigs for US $4.1 billion.

The shipyard giant signed a letter of intent with Sete in April this year. Through its subsidiary, Fernvale Pte. Ltd., it said it had now firmed up those contracts, with the five semisubs to all be based on Keppel’s proprietary DSSTM 38E design. The rigs are scheduled for delivery in 4Q 2016, 3Q 2017, 2Q 2018, 4Q 2018, and 3Q 2019, respectively.

In December 2011, Keppel O&M secured a contract from Sete Brasil to build one semisub to the same DSSTM 38E design. Scheduled for delivery in 4Q 2015, this first rig celebrated the ‘strike steel’ milestone July 13 at Keppel’s BrasFELS yard in Angra dos Reis, Brazil.

These new units also will be built at the same yard in Brazil, Keppel said. When completed, the rigs will be chartered to operator Petrobras for 15 years for drilling activities in Brazil’s offshore pre-salt areas. Three rigs will be operated by Queiroz Galvão Óleo e Gás SA, two by Petroserv SA, and one by Odebrecht Óleo e Gás SA.

The DSSTM 38E design is rated to drill to total depths of 10,000 m (32,810 ft) below the rotary table in up to 3,000 m (9,843 ft) of water. Its operational displacement is approximately 45,000 tons, with each rig able to accommodate a crew of 160.