Abstract

Aging facilities are a common issue within the oil and gas industry. This research demonstrates a practical approach to aging life extension, taking into account risks and constraints, such as budgets, resources and offshore field-level logistics. The case study reviewed is Mubadala Petroleum's (MPs) small, but aging, upstream offshore oil facility located in the Gulf of Thailand, known as the Jasmine/BanYen field. The field includes six offshore platforms, subsea pipelines and a Floating Production, Storage and Offloading asset (FPSO). The field, which commenced production in 2005, was initially expected to have a relatively short field life, and as a result, the facilities were genially specified for only a 10-year lifespan. As the field exceeded expectations in term of volumes and longevity, it became clear to MP management that a practical and cost effective life extension plan was necessary. As such, this research describes the approach to taken by MP to extend the life of the Jasmine/BanYen facilities.

The approach taken by MP was closely aligned with the recommendations and best practices proposed by several regulatory authorities with extensive experience in managing aging offshore oil and gas facilities, such as the United Kingdom's (UK) Health and Safety Executive (HSE) and the Norwegian Petroleum Safety Authority (PSA). As such, the facilities were first functionally decomposed into a number of subsystems, such as Wells, Structures, Pipelines, Topsides, Risers and Floating Assets. A target life extension period was specified, which was followed by a series of focused risk assessments to determine the levels of risk expected during the life extension period, with the critical gaps identified. Each risk assessment involved specialist resources related to the subsystem under review, such as structural engineers, process engineers, marine engineers, instrument engineers, as well as technical safety and environmental engineers. For any risks that were deemed unacceptable, a mitigation plan was suggested and associated costs developed. Finally, a phased master plan was developed that took into account constraints while prioritizing actions based on the determined risk levels.

The implementation of the plan was challenged by the intricacies of offshore logistics, including constraints on supply boats, Persons On Board (POB) etc., and budgetary constraints, which were considerable given the relatively high operational expenses of the field and the low oil price environment. As per the risk assessment, high priority activities were determined to be with respect to FPSO, well integrity and the integrity of subsea pipelines. The platform structures and topsides were considered to be lower priority, as they had already been verified for the life extension period by the company's Asset Integrity (AI) program. Additionally, MP also has a robust Safety Critical Element (SCE) system in place which is an integral part of the AI program, and as such there were no unexpected revelations with regards to the condition of the SCEs. Obsolescence was determined to be a low priority since the equipment on the platforms are relatively new, and most of the Original Equipment Manufacturers (OEMs) provided assurance on the availability of spare parts for the main equipment items.

Highlights of the life extension plan are as follows:

  • Production flexible riser connecting the steel pipeline network to the FPSO has been replaced

  • Pipelines inspections are ongoing, and repairs are being prioritized

  • The design life of platform subsea structures has been extended based on fatigue analysis

  • Subsidence analysis has been carried out on all platforms and indicated no major anomalies

  • Platform power generation facilities are progressively being upgraded

  • A comprehensive well integrity systems have been implemented and critical activities such as barrier testing and well repairs are being carried out regularly

  • Repairs to the hull of the FPSO have been carried out

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