Technology Editor, Subsea & Seismic
PERTH, Australia --A second-generation drill pipe riser design has come out of the deployment of a DPR intervention system in deepwater Brazil. The new version, based on high-performance pipe, combines a double shoulder connection with a metal-to-metal seal.
In a presesntation at the Deep Offshore Technology Conference and Exhibition Asia/Pacific in Perth, Australia, Thomas Peter, Vallourec Mannesmann Oil & Gas France, discussed the development of the new generation system.
The original DPR system was installed in Roncador field in 1,800 m (5,905 ft) in 1999. The target purpose of the DPR was to provide a mobile, early production riser for use on a floating production facility performing extended flow tests of new and recompleted producing wells.
In 2006, development of high-pressure gas production in Espirito Santo basin made improvements in the system necessary in order to handle corrosive gas at 10,000 psi. Improvements in the second generation system include:
• Metal-to-metal seal relocated close to the internal shoulder
• New thread profile with a triangular thread having a reduced angle on the loading flank
• Larger pitch diameter
• Stress relief groove added to the box.
Testing is under way at Golfinho field in 1,608 m (5,276 ft) of water and at 6,000 psi from a semisubmersible.