CIMC Raffles today held naming ceremonies for the OOS Gretha and OOS Prometheus semisubmersible drilling rigs, built at its yard in Yantai, China, and due to work for Petrobras offshore Brazil.
The two units were designed and built by CIMC Raffles. The OOS Gretha is 137.5m-long, 81m-wide, 39m deep (base line to main deck), with a maximum variable load of 7070-ton. It can accommodate 618 people, has a DP3 system, and was classed by ABS.
Image: The OOS Gretha, at Yantai, courtesy CIMC Raffles.
CIMC Raffles said it is the first asymmetric semisubmersible unit without bracing in the world. This reduces the towing resistance and dynamic positioning load, improving sailing speed from an average 8 knots to more than 12 knots.
The asymmetric pontoon outline, with pneumatic de-ballast system, also aids quick ballast adjustment, to suit heavy lifting operation.
The vessel has two 1800-ton offshore mast cranes, which can perform tandem lifting, and it can withstand more than 22m wave height, says CIMC. Its specification means it can work in West Africa, Brazil, Gulf of Mexico and the North Sea, added CIMC.
The sister rig OOS Prometheus, is 118m-long, 70m-wide and 38m-deep, with maximum variable load of 5000-ton. It can accommodate 500 people, has a 1000m maximum operation depth. It was also classed by ABS, has one 1100-ton deck crane, and 3000sq m deck space.
CIMC Raffles previously delivered two deepwater semisubmersible drilling rigs, the SS Pantanal and SS Amazonia, in October, 2010 and April 2011, and both working for Petrobras. The SS Pantanal is now drilling the 14th oil well in the Campos basin, and the SS Amazonia, the 4th well in the Santos basin, said CIMC.