Engineering for Successful Decommissioning

During the development phase of a project, both installation and operational load cases are considered.  Although in some instances a recovery case may be assessed, it is unlikely that this will cover all potential recovery methods, vessels, weather criteria, or the integrity of the installation as it approaches the end of its design life.

This leads to the question: How can this affect decommissioning?

Operators want to spend less on decommissioning so that more can be spent elsewhere, such as exploration.  Therefore, engineering analysis is not always considered a necessary expenditure.  However, PDi has been involved in several different decommissioning projects that have required planned decommissioning methodologies to be amended based on the outcomes of performing engineering analysis.  This includes the decommissioning of subsea structures, risers and pipelines (including flexibles and umbilicals), which will be discussed during the presentation.

Hayley Welsh is a Lead Discipline / Chartered Engineer. During her time at PDi Ltd., she was involved in projects from FEED to decommissioning, where she was responsible for performing installation analysis of pipelines (rigid and flexible) and umbilicals and structure deployment analysis.