OrcaFlex examples

Production risers

Below is a list of links to OrcaFlex example topics. Within each topic are a number of examples which each comprise one or more simulation files, a description pdf file, workspace files and sometimes other supporting files. The files for each example are zipped for easy download. The simulation files can be opened and viewed with the demonstration version of OrcaFlex.

Production risers

A01 Catenary and wave systems

In these examples, four types of riser system are shown: a simple catenary, a lazy wave, a steep wave and a pliant wave.

The examples illustrate:

  • Variation of drag coefficient with Reynolds Number.
  • Bend stiffener modelling.
  • Modelling of buoyancy modules.
  • Extending the simulation.
  • Modelling tethers and their clamps.

A02 Midwater arch systems

In these examples, three types of riser system are shown: a lazy S (both simple and detailed), a steep S and a pliant S. An S configuration is similar to a catenary but has support provided at about midwater by an arch structure.

The examples illustrate:

  • Modelling of midwater arches.
  • Contact between Lines and with Shapes, including friction.
  • Modelling bridles and tethers.
  • Using supports to model arch gutters.
  • Setting the model north pointer.

A03 Jumper to high tower

Flexible jumpers connect a spread-moored FPSO to a high riser tower in deep water, i.e. the tower top is close to the surface. The lines descend to the seabed as rigid structures clamped around the tower. An installation of this type can be found in the Girassol field.

The example illustrates:

  • Modelling bellmouths.
  • Multiple Wave Trains.
  • Modelling a riser tower.
  • Modelling slug flow.
  • Line contact.

A04 Disconnecting turret system

This model represents an FPSO system with a releasable turret. Disconnecting systems are found in regions where typhoons or ice flows are common. It allows the vessel to be removed until conditions improve.

The turret can be lowered from the vessel with winches. However downtime is expensive so operators prefer to keep producing until the last moment then drop the turret and drive off. The turret drops below the severe weather until the FPSO returns to reconnect.

The turret system needs to be designed so there are acceptable responses in all three phases.

  • Connected. The turret is attached to the vessel and moves with it.
  • Disconnecting. The flexibles are disconnected from topside and the turret is released.
  • Disconnected. The turret is settled deeper in the water.

A05 Steel catenary riser systems

This example contains three examples of steel catenary risers (SCRs). These are:

  • Catenary with spar.
  • Catenary with semisub.
  • Lazy wave with FPSO.
The example also illustrates:
  • User specified units.
  • Homogeneous pipe properties.
  • Adding coatings and linings.
  • Modelling strakes.
  • Tapered stress joints (TSJs).
  • Flex joints.
  • API RP 2RD stress code check.
  • Vessel drawing techniques.