Abstract
Several factors can affect the response of steel catenary risers (SCR) around its touch down zone (TDZ). These include the stiffness of the soil, the soil suction force on the riser TDZ, the soil degradation with cyclic TDZ loading, etc. Riser strength and fatigue response computation are usually performed considering flat seabed and with the use of rigid or linear (spring) riser soil interaction model. However, bathymetric information obtained for the SCR lay path on the seabed reveal complex seabed profile variation, indicating that the seabed is far from being flat around the SCR TDZ. This paper presents findings from an investigation conducted on the influence of seabed slopes on the strength and fatigue response of SCRs, using a non-linear (NL) riser soil interaction model. The responses of SCRs on positively and negatively sloped seabed (rotated about the static touch down point on flat seabed) are compared with responses of SCRs on flat seabed. From the results, it can be deduced that the SCR dynamic and fatigue responses may be overpredicted or underpredicted in magnitudes dependent on the slope deviation of actual seabed from a flat seabed.
Highlights
Steel catenary risers are the most attractive riser solution because of their simplicity and robustness in application [1]
Where s is the catenary length from hang off (HO) to touch down point (TDP), x is the horizontal span from HO to TDP, z is the vertical span from HO to TDP, w is the submerged unit weight of pipe section, θ is the HO angle with the horizontal, which can be expressed as (tan−1(V/H)), H is the horizontal components of tension, V is the vertical components of tension, and T is the resultant tension force of H and V
Such errors can impact on the design of the steel catenary risers (SCR) whose sections around the TDP are to be cladded with carbon resistive alloys (CRA) to reduce corrosion induced fatigue damage
Summary
Steel catenary risers are the most attractive riser solution because of their simplicity and robustness in application [1]. Prediction of SCR stress and fatigue response around the TDZ was in the early history of SCR design performed using a rigid soil model. This approach was progressively improved by the development and implementation of linear (spring) soil-riser interaction models. Considerable efforts have been made to improve the SCR TDZ interaction model by the development of the non-linear models [24]. The NL riser soil interaction model provides a more realistic approach for evaluating riser response interactions with the seabed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: IOP Conference Series: Materials Science and Engineering
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
