Session: 04-05-02 Subsea Structures & Equipment II

Submission Number: 176025

Analysis of Monitored and Simulated Loads for Riserless Well Intervention Operations in Shallow Waters 

This paper presents an analysis of monitored and simulated loads for operations using the Riserless Well Intervention (RLWI) system. Analysis is focused on Riserless Coiled Tubing (RLCT) operations in shallow waters at depths of 70 and 130 meters. The RLWI system offers advantages such as cost efficiency and reduced environmental impact in comparison with traditional riser-based operation. Monitoring of structural loads and deformation of the subsea stack during RLWI operations provides essential data for simulation and system calibration.

Calibration of load estimates, involving controlled tests and simulations, ensures that measured loads match actual structural loads. This process allows for the refinement of measurement techniques and validation of the monitoring system’s accuracy. The methods used and the improvements achieved are described.

The measured loads are compared with results from dynamic structural simulations using advanced computational models to predict structural loads and motions under various scenarios. Analyzing discrepancies between measured and predicted loads leads to improvements in both the monitoring system and simulation models.

Operating envelopes for the RLWI system are established based on measured and simulated data, defining operational limits. The study also addresses fatigue loading, which is crucial for the long-term performance and reliability of the subsea stack. Fatigue analysis, using both measured and predicted loads, offers a comprehensive understanding of the structure’s fatigue life under various conditions.

The findings demonstrate the RLWI monitoring system’s effectiveness in enhancing operational capabilities and ensuring structural integrity in shallow waters, particularly for RLCT applications. Continuous monitoring and calibration of structural loads yield crucial insights into the subsea stack’s behavior, contributing to the optimization of operational procedures and improvement of system reliability.

Presenting Author: Lasse Moldestad TechnipFMC

Presenting Author Biography: Educated M.Sc. Marine Technology at Strathclyde University and University of Glasgow, Department of Naval Architecture and Marine Engineering in 2005. 20 years of experience working mainly with global riser analysis of rigid risers, marine riser operations, completion/workover intervention, top tensioned risers and riserless well intervention. Additionally, experienced in hydrodynamic analysis of mono-hull and semi-submersible vessels, marine operations, structural local finite element analysis, vortex induced vibration analysis, station keeping / mooring analysis, analysis of floating bridge, availability analysis and more. I have worked with structural and functional component testing. Have developed three systems for processing of global riser analyses using commercial analysis solver and developed software for mooring line catenary calculation. I have one patent on a guidepost locking mechanism. One previous OMAE presentation as main author and presenter in 2022 on effect of current on riser and wellhead fatigue, using advanced analysis methods. In recently years I have worked extensively with riserless well intervention and specifically coil tubing operations, processing and comparing monitoring of the subsea stack with vessel position logging and simulations.

Authors:

Lasse Moldestad TechnipFMC
Halvor Gustad TechnipFMC
Mathias Hansen TechnipFMC
Andrea Leone TechnipFMC
Per Thomas Moe TechnipFMC