GIRASSOL Risers & Flowlines


DORIS was in charge of developing a novel riser concept meeting the challenges of such deepwater development, the deepest ever off West Africa.

The search for a versatile, reliable and cost effective solution opened the way to the Riser Tower Concept.

The proposed solution is based on the use of sealine bundles and self-supporting hybrid riser towers housing the production, water/gas injection, gas lift and service lines in a single piece of equipment.

The production flowlines use a new bundle technology whereby two 8-inch production lines are installed inside a 30-inch carrier pipe. Syntactic materials placed inside the bundle provide the required buoyancy as well as a level of insulation.

The towers are connected to the FPSO through flexible jumpers and to the flowlines by jumper spools.


Services provided by DORIS Engineering:

  • Concept definition and development within a design competition (1997)
  • Front end engineering and preparation of MTO’s for submission to ELF (first half of 1998)
  • Detailed engineering (from mid-1998 to 2001)
  • Model tests for towing and in-place conditions through DORIS subsidiary OCEANIDE (2000)
  • Assistance to AMG for Girassol Phase 2 and Jasmim development (2002)
GIRASSOL Risers & Flowlines

Main characteristics:

  • Flowlines: Two 8-inch prod. lines (+ two 2-inch service lines) inside a 30-inch carrier pipe
  • Riser towers: Four 8-inch prod. lines along with a gas lift line and two 8-inch injection lines (water or gas)
  • Buoyancy tank: 40 m high; ø 8 m; 1,300 m3 displacement
Deepest project ever in 1998
World first: riser towers, bundle technology
  • Project

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