Enhancing Offshore Installation Decision-Making Through the Integrated Application of Vessel Motion Based Criteria (VMBC) Methodology and Digital Tools

Abstract

Abstract Optimized decision-making processes for offshore installation operations is paramount to ensure both safety and efficiency, dependent upon reliable evaluations of prevailing environmental conditions. Traditionally, operational determinations have depended on the consideration of significant wave height (Hs) and wave period (Tp) limits. However, a shift in this domain has been challenged by Subsea 7 through the inventive "Vessel Motion Based Criteria, VMBC" methodology. The VMBC methodology encompasses two central tasks, jointly contributing to an integrated decision support structure: First and foremost, the identification of variables steering installation activities, such as the dynamic behavior of flexible risers, optimal gooseneck landing speeds, and critical crane top tension, forms the bedrock. Then by establishing correlations between these key parameters and the vessel's motion at predefined points of interest, termed as control variables, a well-defined threshold for maximum allowable vessel motions is derived. This threshold, represented through extreme value statistical parameters and indicative of operational limits, forms the cornerstone of safe and efficient operation planning. The second is the development of a digital tool mirroring real offshore processes, ensuring that insights derived are directly applicable to operational scenarios. The digital tool streamlines the data collection process of the latest weather forecast and sensor data and automates the calculation of activity feasibility. This is done by utilizing the potential of metocean forecast reports, encompassing directional wave spectra and the vessel's response amplitude operators (RAOs), to numerically assess probable motions many days in advance. This empowers offshore stakeholders to plan and assess upcoming activities based on accurate prediction of vessel response with the objective of reduced waiting on weather without compromising safety. This paper introduces an enriched understanding of how the VMBC method is used in real life operations. A methodology is presented that integrates applied theory with sensor technology and cutting-edge digital tools to deliver a more refined perspective on offshore operation planning and control. The paper culminates in a use case presentation, spotlighting the VMBC method in action and opportunities for more accurate determination of operability. This practical illustration shows the method's tangible benefits and the value of its integration with digital tools.