Understanding the response of the drilling riser in ultra-deep water is critical for effective riser management and successful drilling operations. Due to the relative shortage of industry experience in ultra-deep water, analysis conducted prior to an operation is a key supplement to judgement and common sense. Damage or loss of the riser or the BOP leads to high costs for riser replacement and rig downtime. The riser can be subjected to various loading configurations during a drilling operation. Storms and/or high current conditions can be encountered while the riser is in the following configurations: deployment; connected and tensioned; subjected to vessel drift-off; subjected to recoil after and emergency disconnect; and suspended in a hang-off conditin. The unique aspects of each of these riser loading configurations in ultra-deep water warrant careful attention by riser analysts to provide operations personnel with well-founded guidance and an idea of what to expect in the field. This paper provides an overview of the key elements of drilling riser analysis in ultra-deep waters. analysis results are presented on the topics listed above, along with operational applications for several ultra-deep water drill ships. Shortcomings and uncertainties in riser analysis are discussed. The resutls show that analysis of key drilling riser configurations is critical for understanding riser response during operations and effective riser management.
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