As an operator, Total has experienced significant deepwater maintenance and repair activities, including cut-out and replacement of a damaged section of water-injection line, replacement of a flexible riser, replacement of an anchor line and its pile, and repair of an umbilical termination head (UTH).
There are few deepwater-pipeline operators with experience in pipeline repairs that need to be carried out with significant preparation time for intervention tools, including engineering and testing of the tools.
Deepwater operations [including inspection, maintenance, and repair (IMR)] require a completely different paradigm than conventional offshore operations, with need for specialized competencies, contractors, and tools. The pipeline-repair activities mastered in conventional offshore operations are becoming difficult tasks in deep water because they have to be performed remotely and the pipeline characteristics are quite different. Furthermore, there are many important challenges that still need to be overcome, such as repair of pipe-in-pipe systems, repair of production bundle, repair of flowline with hydrogen sulfide content, and repair of flowline connection, all of which challenge research and development to find proper tools and methodologies for deepwater intervention.
This paper describes the strategy developed and implemented on deepwater-pipeline intervention, based on a deepwater operational experience built over a decade. It also presents experiences of dealing with integrity issues and how to move forward in existing operations while preparing for future developments. Once the proper technologies are acquired, a pipeline-repair system should be established as part of an operational-management philosophy.
From the design stage, an operator involved in the development of deepwater operations should give serious consideration to how condition monitoring of the pipeline and its appurtenances will be performed and to how pipeline sections will be repaired or replaced should there be any failure during production. Being well prepared to face unexpected failures in the deepwater-pipeline network would allow the operator to maintain the level of integrity of the deepwater-pipeline network, minimize production loss and shortfall, minimize intervention costs, and maintain the operator’s image with international media and the national oil company.