During 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 location and target location determination, transfer function generation, calculation of acceleration power spectral density (PSD) at monitoring location, analysis of response parameter PSD at target location, post-processing for response parameter. Numerical experiment method with a 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 for comparison. The validation results show that the results from TF method good coincidence with the theoretical results. Study on an actual 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 and actual monitoring results discussion can be a significant basis and valuable reference for deepwater drilling engineering.
The oil and gas industries are experiencing increasing competition and have already reached a saturation state in inland areas; thus, potential production areas are being extended to coastal and open oceans around the 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 the in-situ drilling riser monitoring systems in order to support drilling operation, hang-off or transit operation and confirm the structural integrity of their requirement (Keprate, 2015). The riser monitoring data facilitates decision making during extreme or unusual events can help prevent costly delays. The sensor-based structural monitoring plays a crucial role in detecting any malfunction or initial damage of riser/mooring and preventing subsequent failure (Kim, 2021). An available way to monitor the drilling riser and check its structural robustness and fatigue life is to analyze elastic responses parameter. The dynamic response of the drilling riser system is one of the most important drivers for the use of monitoring systems. In comparison to FEM or other analysis methods, the monitoring data presents the strength results directly with a higher level of accuracy.
