Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Dynamic Response Prediction for Hang-off Drilling Riser Based on Measured Acceleration Data
Jinlong Wang, Liwei Li

CNOOC Research Institute Ltd., Beijing, China

ABSTRACT

integrity of their requirement (Keprate, 2015). The riser monitoringdata facilitates decision making during extreme or unusual events canhelp prevent costly delays. The sensor-based structural monitoring
plays a crucial role in detecting any malfunction or initial damage ofriser/mooring and preventing subsequent failure (Kim, 2021). An
available way to monitor the drilling riser and check its structuralrobustness and fatigue life is to analyze elastic responses parameter.
The dynamic response of the drilling riser system is one of the mostimportant drivers for the use of monitoring systems. In comparison toFEM or other analysis methods, the monitoring data presents thestrength results directly with a higher level of accuracy.
During hang-off or transit operation, some acceleration loggers areinstalled on the drilling riser at some concerned locations. However,
due to the limit of installation time and logger number, the whole riser
response cannot be monitored and captured. How to predict the
response distribution along the whole riser, like acceleration amplitude,
displacement, bending moment or stress distribution, based on themeasured motion data at limited monitoring locations are a technology
challenge for the drilling riser system.
Some research have been conducted on drilling riser measured sensor
data assessment technology and several methods have been developed.
Various types of sensors are used for riser monitoring, such as
accelerometer, strain gauge, inclinometer, angular velocity sensors,and curvature sensors (Thethi, 2005; Cook, 2006; Podskarbi, 2006;
Podskarbi, 2007; Karayaka, 2009a and 2009b; Peng, 2012; Mercan,2016). The acceleration logger is most commonly used and there aremainly 3 methods to assess the acceleration dada to obtain the
structural response and fatigue performance: analytical method, mode
matching method and transfer function method. Analytical method cananalyze the response or fatigue at monitoring location, however,cannot predict other locations. Mode matching method focuses on theriser response due to vortex induced vibration (VIV) during high ocean
current event based on mode shape reconstruction in which the riser
response is calculated for the mode amplitude and frequency fitting
best into the measured riser response at various logger locations(Beynet, 2008; Kaasen, 2000; Natarajan, 2006; Shilling, 2005;
Tognarelli, 2008). However, during the hang-off or transit operation,
the wave induced motions and VIV exist simultaneously in mostDuring hang-off or transit operation, the monitoring systems is an
important measure to keep the integrity and safety for drilling riser.
The risers’ dynamic response prediction based on measured
acceleration date from limited acceleration loggers is a technology
challenge. A prediction method for dynamic response of hang-off
drilling riser based on measured acceleration data and transfer function(TF) theory are proposed and detailed calculation process is developed.
The prediction methods contains five procedures: monitoring locationand target location determination, transfer function generation,
calculation of acceleration power spectral density (PSD) at monitoring
location, analysis of response parameter PSD at target location, postprocessing for response parameter. Numerical experiment method witha hang-off drilling riser monitoring assessment case in 2000m water
depth is introduced to validate the accuracy of the proposed response
prediction method and a numerical experiment case is discussed forcomparison. The validation results show that the results from TF
method good coincidence with the theoretical results. Study on anactual monitoring case with 20 events for drilling riser under hang-off
operation are conducted and the response parameters are derived. The
proposed prediction method, numerical experiment validation andactual monitoring results discussion can be a significant basis andvaluable reference for deepwater drilling engineering.
KEY WORDS: Hang-off drilling riser; Response prediction; transferfunction; numerical experiment; measured acceleration dataINTRODUCTION
The oil and gas industries are experiencing increasing competition andhave already reached a saturation state in inland areas; thus, potential
production areas are being extended to coastal and open oceans aroundthe globe (McNeill, 2014; Kawsar, 2015; Xu, 2017). The frequently
hurricanes and typhoons occurred that battered the offshore facilities
have prompted many operators and drilling contractors to install thein-situ drilling riser monitoring systems in order to support drilling
operation, hang-off or transit operation and confirm the structural1805