Dynamic Plastic Deformation of Deepwater Steel Catenary Risers Under Extreme Cyclic Compressive Loading
Steel catenary risers (SCRs) on a large-heave-motion vessel are susceptible to compression in the riser touchdown zone (TDZ). Dynamic compression can lead to overstress under extreme or abnormal weather conditions. The response of an SCR under compression is highly nonlinear and sensitive to various factors. However, the current available industry design codes and practices do not provide a clear guidance to address the acceptability of compression, overstress, and the resulting plastic strains. In addition, the current analysis method used in industry common practice cannot capture accurately the nonlinear behavior of an SCR involving accumulated plastic deformation, hysteresis effects, and local buckling.
In this paper, a finite-element-analysis modeling method that uses combined beam and solid elements is presented. This method enables simulation of large plastic deformation, pipe ovality, and local pipe buckling in the TDZ of a deepwater SCR. The model is developed with Abaqus (Dassault Systèmes 2009). The SCR non- linear response is examined through dynamic analysis of a deep- water SCR that is hung from a semisubmersible. The key analysis results are compared with a nonlinear beam-element model. More- over, dynamic-ratcheting analysis under multiple plastic-strain cycles by use of the proposed solid-riser model is conducted to understand the plastic-strain accumulation and to check the acceptability of the survival response of a deepwater SCR under a series of severe hurricanes in its service life.
This paper presents the methodology for evaluating the compression and plastic deformation that could be experienced by deepwater SCRs, including the modeling approach, analysis results, possible failure modes, and conclusions. The impact of the study findings on the robustness and suitability of SCRs for deepwater application is discussed.
Water Outside the Permian: How Are Other Basins Handling the Volumes?
The Permian gets the lion’s share of attention when it comes to produced water, but other basins have a need to haul volumes off-site. How has the market changed in these areas recently? Is there a greater enthusiasm for pipelines, and can water midstream thrive?
New Pipelines Needed to Meet Surge in Permian Crude Demand
Growing supply of Permian crude oil means the basin will need extra takeaway capacity of up to 500,000 B/D by the end of the 2020s, according to new research from Wood Mackenzie.
McDermott Completes First Installation Campaign for R-Cluster Project Offshore India
Completion comes despite two cyclones disrupting the project area during installation, McDermott said.
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