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Shock and Vibration
Volume 2018, Article ID 6568537, 15 pages
https://doi.org/10.1155/2018/6568537
Research Article

Coupled Dynamic Analysis for the Riser-Conductor of Deepwater Surface BOP Drilling System

1School of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, China
2Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John’s, NL, Canada

Correspondence should be addressed to Kanhua Su; moc.621@auhnakus

Received 31 May 2017; Accepted 21 November 2017; Published 11 January 2018

Academic Editor: Yuri S. Karinski

Copyright © 2018 Kanhua Su et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Deepwater surface BOP (surface blowout prevention, SBOP) drilling differs from conventional riser drilling system. To analyze the dynamic response of this system, the riser-conductor was considered as a beam with varied cross-sections subjected to loads throughout its length; then an equation of motion and free vibration of the riser-conductor string for SBOP was developed. The finite difference method was used to solve the equation of motion in time domain and a semianalytical approach based on the concept of section division and continuation was proposed to analyze free vibration. Case simulation results show that the method established for SBOP system natural frequency analysis is reasonable. The mode shapes of the riser-conductor are different between coupled and decoupled methods. The soil types surrounding the conductor under mudline have tiny effect on the natural frequency. Given that some papers have discussed the response of the SBOP riser, this work focused on the comparison of the dynamic responses on the wellhead and conductor with variable conditions. The dynamic lateral displacement, the bending moment, and the parameters’ sensitivity of the wellhead and the conductor were analyzed.