AI
Tuesday, March 18, 2008 8:09:28 AM
Interesting photos, somebody once asked if we do any work for Petrobras (PBR)
" As flexible pipe applications move into deepwater and ultra deepwater, attention is focused on enhancing service life, particularly with respect to corrosion and wearing. In Brazil’s offshore Campos basin, Petrobras and Wellstream International Ltd. have addressed both issues for unbounded dynamic flexible risers and static flowlines.
The first means of enhancing service life is the use of a latch sleeve insert to address damage in flexible risers caused by friction between the outer polymer sheath of the riser and the I-tube at the vessel hang-off. The second is the use of anode clamps to protect flexible pipe endfittings against corrosion.
Petrobras’ original I-tube latch sleeve had a metallic “trumpet” that interfaces directly with the bend stiffener within the I-tube for a metal-polymer contact between the flexible riser outer sheath and the latch sleeve.
New latch sleeve design.
This metal-polymer contact, when subjected to cyclic bending, tension, friction, and pressure loads from the FPU’s dynamic response, resulted in excessive wear and abrasion damage of the riser polymeric outer sheath. In some cases, the outer sheath was damaged to the point that the outer tensile wires were exposed to the marine environment and subject to failure from corrosion and metal-metal contact. Furthermore, Petrobras found that outer sheath wear damage was critical on FPSO installations. Damage came from axial displacement of the riser inside the I-tube causing outer sheath (polymer) friction against the internal surface of the latch sleeve (metallic).
Wellstream developed a new latch sleeve design to eliminate excessive wear of the riser outer sheath material within the contact region. The sleeve was designed for a 20-year dynamic service life in a typical Campos basin application.
The latch sleeve mechanism has an internal replaceable insert made of similar materials to those used in typical bend stiffener moldings. The polymer-polymer contact is similar to that between the riser outer sheath and the bend stiffener. The new latch sleeve still has a trumpet design for a smooth transition of the flexible riser within the contact region.
The design was based on the following:
* In-service survey data
* Petrobras’ requirements
* Bend stiffener supplier design and field experience
* Full-scale dynamic fatigue tests and subsequent detailed dissection.
http://www.offshore-mag.com/Articles/Article_Display.cfm?Article_ID=312416
" As flexible pipe applications move into deepwater and ultra deepwater, attention is focused on enhancing service life, particularly with respect to corrosion and wearing. In Brazil’s offshore Campos basin, Petrobras and Wellstream International Ltd. have addressed both issues for unbounded dynamic flexible risers and static flowlines.
The first means of enhancing service life is the use of a latch sleeve insert to address damage in flexible risers caused by friction between the outer polymer sheath of the riser and the I-tube at the vessel hang-off. The second is the use of anode clamps to protect flexible pipe endfittings against corrosion.
Petrobras’ original I-tube latch sleeve had a metallic “trumpet” that interfaces directly with the bend stiffener within the I-tube for a metal-polymer contact between the flexible riser outer sheath and the latch sleeve.
New latch sleeve design.
This metal-polymer contact, when subjected to cyclic bending, tension, friction, and pressure loads from the FPU’s dynamic response, resulted in excessive wear and abrasion damage of the riser polymeric outer sheath. In some cases, the outer sheath was damaged to the point that the outer tensile wires were exposed to the marine environment and subject to failure from corrosion and metal-metal contact. Furthermore, Petrobras found that outer sheath wear damage was critical on FPSO installations. Damage came from axial displacement of the riser inside the I-tube causing outer sheath (polymer) friction against the internal surface of the latch sleeve (metallic).
Wellstream developed a new latch sleeve design to eliminate excessive wear of the riser outer sheath material within the contact region. The sleeve was designed for a 20-year dynamic service life in a typical Campos basin application.
The latch sleeve mechanism has an internal replaceable insert made of similar materials to those used in typical bend stiffener moldings. The polymer-polymer contact is similar to that between the riser outer sheath and the bend stiffener. The new latch sleeve still has a trumpet design for a smooth transition of the flexible riser within the contact region.
The design was based on the following:
* In-service survey data
* Petrobras’ requirements
* Bend stiffener supplier design and field experience
* Full-scale dynamic fatigue tests and subsequent detailed dissection.
http://www.offshore-mag.com/Articles/Article_Display.cfm?Article_ID=312416
My posts are my opinions. Always dd to your own comfort level.
