Prosafe Production’s Azurite unit is now in operation off the Republic of Congo. DNV was selected to provide classification and verification services.
Azurite is meant to handle not only the production of oil, like a traditional FPSO, but also production well drilling. The Floating Drilling Production Storage Offloading (FDPSO) unit is equipped with a modular drilling package that can be removed and reused elsewhere when the drilling work is completed. The storage capacity is of 1.4 million barrels of oil and a process capacity of 60,000 barrels of fuel per day and 40,000 barrels of oil. It will be spread-moored in a water depth of 1,400 metres.
15-year life extension
“When the ‘Azurite’ left Singapore’s Keppel Shipyard for West Africa, a new era of oil and gas production began, as it became the first self-contained vessel with the ability to drill several wells within the first three years after its arrival on location,” explains Johan Gärdin, head of DNV’s Offshore Classification department in South East Asia.
Formerly a Very Large Crude Carrier, Azurite underwent a conversion between July 2007 and February 2009. The life extension programme involved assessments of global and local strength, fatigue life analysis for critical connections and replacement of structural steel as well as preparations for periodical in-water surveys. Azurite’s new design means she has a 15-year extension, in which she will remain in the Mer Profonde Sud block, operated by Murphy West Africa Ltd, off the Republic of Congo.
Safety philosophy
The drilling facility resembles a typical offshore rig, but with a surface Blow Out Preventer, which is placed in a central moon pool.
Problems that required solutions during the conversion and classification processes included the physical arrangement of adjacent process and utilities modules with their associated structures, such as piping and cabling. Mitigating the effect of motions was also necessary. Additionally DNV assisted Prosafe Production with the creation of a coherent safety philosophy when combining two different ongoing activities subject to different regulations.
Particularly interesting topics like definition of accidental loads, shut down logic, area classification and fire fighting were examined. These were adressed within the framework of existing DNV Offshore Specifications and Standards with a certain amount of interpretation and prioritizing between them.
The process plant design was verified by DNV guided by their Offshore Standards and Rules as templates that were modified according to Prosafe’s specification. The majority of topsides equipment was also required by Prosafe to have DNV certification. Besides that, all major safety aspects have been covered by the main class.
Singapore Offshore Class Centre
Both plan approval and site surveys were coordinated and executed by the DNV’s Offshore Class Centre in Singapore, which since its inception in 2006 has been expanded to efficiently handle all aspects of conversions, newbuildings and units in operation. In most respects, the Centre now acts as a one-stop-shop for customers like Prosafe with local engineering offices.