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.
Pembina Pipeline To Acquire Kinder Morgan Canada in $4.35-Billion Deal
Calgary-based Pembina Pipeline Corp. has entered into agreements to acquire Kinder Morgan Canada Ltd. and the US portion of the Cochin Pipeline system from Kinder Morgan for a total purchase price of approximately $4.35 billion.
Swire Seabed Completes Autonomous Pipeline Inspection for Equinor
The subsea operations company said its most recent campaign is the first fully unmanned offshore pipeline inspection completed “over the horizon,” surveying up to 100 km from the shore.
First Permian Crude Delivered From Cactus II Pipeline
Trafigura confirmed that it had begun shipments from the Permian to Corpus Christi via the pipeline, which has a 670,000-B/D capacity. Operator Plains All American announced last week that it had completed work on the pipeline.
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