Oil and gas industry experts at TWI have carried out more than 1,000 confidential projects on the design, performance and maintenance of risers, particularly steel catenary risers (SCRs).
A riser is a specially constructed pipe that delivers fluid between subsea equipment and surface bodies such as platforms, floating production storage and offloading vessels (FPS and FPSOs), and drill platforms.
There are several types of risers in use:
- Flexible risers
- Free-standing or top-tensioned rigid risers
- SCRs
Steel catenary risers (SCRs)
SCRs are the most popular riser for use in deepwater applications. They provide significant advantages over 'conventional' flexible or 'hybrid' free-standing risers, with increasing water depth and riser diameter in terms of weight, induced environment loading and cost.
However, to ensure the long-term integrity of these risers, it is essential to carry out a detailed analysis of joint design and fatigue performance over a wide range of loading conditions - from the splash zone to the touchdown region and the interface to the host installation. Over this range, environmental, geometric and mechanical conditions impose varying degrees of tension, bending and fatigue loading. Thus the integrity of the riser will be determined by the response of girth welds to these complex loading conditions.
TWI's multi-disciplinary team provides confidential research to help Member companies ensure the long-term integrity of risers, and also undertakes work to facilitate the installation of SCRs.
For more information, please email contactus@twi.co.uk.