Improving the Free Span Analysis of Subsea Rigid Pipelines for Life Extension Through Integration and Automation and Efficiency

Abstract Free span analysis is essential for the integrity management and life extension of subsea assets at Petrobras. It ensures operational safety and efficiency, minimizes environmental impacts, and supports the company's long-term sustainability goals. This paper presents IntegriSpan, a specialized digital web application developed for the integrated structural and VIV analysis of free spans in subsea rigid pipelines. The application is designed to improve integrity management, simultaneously reducing costs and saving time. To address the challenge of assessing the integrity of thousands of kilometers of subsea pipelines, Petrobras, in collaboration with national science and technology institutes, developed a specialized digital web application aligned with Industry 4.0, focused on integrated structural and VIV analysis of free spans in subsea rigid pipelines. The current version of the application facilitates data querying and sharing with commercial software, environmental databases, and external inspection data from multibeam ROVs within the company's collaborative web portal, SUBWEB. This automation and integration streamline the analysis process, reduce simulation time, enhance data security and integrity, simplify results visualization, and standardize report generation. IntegriSpan has been successfully implemented at Petrobras, optimizing the subsea pipeline integrity analysis process, reducing the time of analysis cycles and the amount of pipeline interventions, and enabling more realistic simulations. An application example presented in this article involves fatigue life assessment in free spans of a large-diameter gas export pipeline, where the initial recommendation for mitigating potential VIV issues was reduced from 120 to 6, avoiding the need for around 400 days of support vessel activity and significantly reducing the time required for an analysis of this magnitude. Currently, the application is also being considered for the assessment of free spans on scouring seabed, a phenomenon detected in some of the company's pipelines. Although several scour onset and progression models are available in the literature, most of the pipeline design codes lack an assertive approach. Through its efficient integrated structural analysis, IntegriSpan is expected to enable the assessment of these free spans considering different scour progression rates taken from field statistical measurements. The traditional process of VIV fatigue analysis in free spans is costly and prone to errors due to manual searches for unstructured information and execution in separate steps. The application addresses these current gaps in pipeline integrity management by providing an integrated, efficient, and accurate assessment method. This innovation enhances operational efficiency and environmental safety in the petroleum industry, offering significant advancements in subsea pipeline management.