Session: 04-01-07 Flexible Pipes & Umbilicals VII

Paper Number: 132224

132224 - Study on the Collision Probability of Tandem Flexible Risers Based on the Extremum Statistical Methodology 

This paper aims to develop an integrated model for predicting the probability of a riser collision. This model can fully utilize the limited time series samples and greatly reduces the computational time consumption required to accumulate enough data samples. Firstly, considering the current, random wave, top motion, and hydrodynamic interference effects, a global mechanical model for the dual-riser system is constructed based on the vector form intrinsic finite element. Then, to obtain a random time series sample of the minimum distance, an analytical geometry-based procedure is coded to identify the minimum distance between risers in real-time during a duration. The distribution parameters of the samples for various extreme value distribution types are determined by the maximum likelihood estimation. The chi-square test criterion, histograms, and quantile plots are used together to further assess the goodness of fit of the theoretical model to the samples, and determine the optimal probability distribution form. Based on this optimal extreme value distribution model, the crossing rate of the sample is extrapolated to the failure threshold to predict the collision probability. OrcaFlex is used to verify the validity of the global dynamic response analysis module. Moreover, the accuracy of the probability prediction module is doubly verified by Monte Carlo simulation and the Gumbel probability paper method. Finally, the effects of critical parameters (i.e., initial spacing, top tension, and reduced velocity) on the collision probability of two flexible risers arranged in tandem are investigated.

Presenting Author: Honglu Gu Ocean University of China

Presenting Author Biography: The presenting author is currently studying for a Ph.D. degree at the College of Engineering, Ocean University of China, majoring in Port, Coastal and Offshore Engineering. The main research interest of the authors focuses on the study of the three-dimensional nonlinear global mechanical behavior of flexible deep-water pipelines. The presenting author has published several scientific papers as the lead author in outstanding journals in this field. He has much research experience with deep-water flexible pipelines and can give a good presentation.

Authors:

Honglu Gu Ocean University of China
Haiyan Guo Ocean University of China
Fanshun Meng Ocean University of China
Xiaomin Li Ocean University of China
Fuheng Li Ocean University of China