Classification for Largest Ever Semi-Submersible Drilling Rig

NORWAY – SOUTH KOREA – US – WORLDWIDE – Classification society DNV GL, founded in Norway but these days an international body, has welcomed the world’s largest semi-submersible drilling rig into class recently. Christened Ocean Greatwhite the rig is to be a new design MOSS CS60E high specification state-of- the art semi-submersible drilling unit suitable for operations in harsh environments, which is the first MOSS CS60E and the largest rig in the world.

Delivered at Hyundai Heavy Industries (HHI) in Ulsan, South Korea for owners the Houston-based drilling contractor Diamond Offshore, the 123 metre long, 78 metre wide rig will be chartered to oil major BP and will operate in the Great Australian Bight. Karl Sellers, SVP Technical Services at Diamond Offshore commented:

“The Ocean Greatwhite is a unique rig purposely built for drilling in harsh environments. HHI and DNV GL were integral in helping us get this rig to market as we prepare for the drilling project in Australia with BP.”

Ocean Greatwhite is also the first new-build rig to receive the DNV GL Integrated Software Dependent Systems (ISDS) notation. ISDS are systems whose performance is dependent on the overall behaviour of their integrated software components. DNV GL’s ISDS standard helps owners and operators minimise software integration errors and delays in projects involving complex integrated systems. Paal Johansen, Vice President and Regional Director, Americas at DNV GL said:

“Ocean Greatwhite is capable of operating in depths of up to 3000 metres and can drill down to a depth of 10,670 metres. It represents the state of the art in the semi-submersible sector and we are very pleased to have been asked to contribute our expertise to this project. We expect that the operational performance of Ocean Greatwhite will demonstrate how the ISDS notation can contribute to increasing the reliability of the complex systems on board.”

The certification ensures that software and integration issues are identified and resolved early on during the project design stages. It also represents a new approach to verification, as it emphasises a review of the working methods and processes that lead to the delivery the systems, rather than simply focusing on the final review of documents and installations to ensure they meet product requirements.

Industry data suggests that high specification mobile offshore drilling units may experience 30% down-time during their first years of operations, which makes a systematic framework for ensuring that ISDS achieve the required reliability, availability, maintainability and safety essential. DNV GL’s ISDS teams in Korea, Norway, and the USA all contributed to the project whilst DNV GL also provided advisory services to HHI on the integration of the various systems throughout the newbuilding process, something obviously appreciated by the shipbuilder with Youngseuk Han, Senior Executive Vice President at HHI observing:

“We have a strong relationship with both DNV GL and Diamond Offshore – and it is thanks to this good cooperation that the project went so well. We are proud to deliver the first drilling ship of this size and look forward to many more projects on this scale. We will keep moving the boundaries of technology by completing following large-scale and innovative projects.”

Photo: Courtesy of HHI.