Dynamical mechanics behavior and safety analysis of deep water riser considering the normal drilling condition and hang-off condition. (1st March 2020)

• Record Type: Journal Article
• Authors: Mao, Liangjie; Zeng, Song; Liu, Qingyou; Wang, Guorong; He, Yufa
• Is Part Of: Ocean engineering. Volume 199(2020)
• Publication Date: 2020-03-01
• Subjects: Drilling riser -- Deep water -- Finite element method -- Rotation angle limitation -- Safety; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2020.106996
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: A dynamic analysis model for the drilling riser was established and applied under normal drilling and hang-off conditions by distinguishing the boundary condition. This model was discretized by the FEM and solved by Newmark β method. The correctness of this model was verified through an experiment. Results indicate that the lateral displacement distribution and riser stress increase with the current speed and platform drift distance. A platform that drifts along the current is conducive to counteract the rotation of the upper joint but promotes the rotation of the bottom joint of the riser. A riser that is approximately 2, 000 m long under normal drilling condition can withstand the current loads for a 10-year return period. The hang-off riser should be evacuated after being disconnected from the bottom along with the current as soon as possible. In addition, the riser that evacuated under soft hang-off condition can significantly reduce stress but enlarge the rotation angle of the upper flexible joint. Graphical abstract: Image 1 Highlights: Established a unified analysis model of deep water riser considering normal drilling and hang-off conditions. The analysis model is discretized by finite element method and solved via Newmark β method. Verified the model by conducting a similar experiment in a deep-water basin. Discussed the dynamic mechanical behavior and safety of riser under different working conditions and loads.