Chapter 22: Design of Deepwater Risers

Chapter 23: Design Codes for Risers and Subsea Systems

Chapter 24: VIV and Wave Fatigue of Risers

Chapter 25: Steel Catenary Risers

Chapter 26: Top Tensioned Risers

Chapter 27: Steel Tube Umbilical & Control Systems

Chapter 28: Flexible Risers and Flowlines

Chapter 29: Hybrid Risers

Chapter 30: Drilling Risers

Chapter 31: Integrity Management of Flexibles and Umbilicals

22.1.1 General

A riser system is essentially conductor pipes connecting floaters on the surface and the wellheads at the seabed. There are essentially two kinds of risers, namely rigid risers and flexible risers. A hybrid riser is the combination of these two.

The riser system must be arranged so that the external loading is kept within acceptable limits with regard to:

• Stress and sectional forces

• VIV and suppression

• Wave fatigue

• Interference

The riser should be as short as possible in order to reduce material and installation costs, but it must have sufficient flexibility to allow for large excursions of the floater.

22.1.2 System Descriptions

The riser system of a production unit is to perform multiple functions, both in the drilling and production phases. The functions performed by a riser system include:

• Production/injection

• Export/import or circulate fluids

• Drilling

• Completion & workover

A typical riser system is mainly composed of:

• Conduit (riser body)

• Interface with floater and wellhead

• Components

• Auxiliary

22.1.3 Flexible Riser Global Configuration

Flexible risers can be installed in a number of different configurations. Riser configuration design shall be...