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This paper summarizes practical experiences after 2 years of use of an online multiphase flow transient simulator in an operating deepwater blackoil field offshore Angola. FAMS (Flow Assurance Management System) is based on state of the art thermal-hydraulic models from bottomhole to slug catcher outlet interfaced to live field instrumentation data. The application is accessed via a web-based graphical interface. Lessons learned presented here cover technical aspects of the tool such as reliability and accuracy under different scenarios, as well as non-technical issues such as system support model and interaction between supplier and end users. Taking transient simulation models; which are traditionally restricted to project development stages, into a real-time environment can have a positive impact on Flow Assurance workflows; particularly around minimizing effort in complex thermal-hydraulic studies, planning of unforeseen operations, training of junior engineers, validation of models and identification of code capabilities and limitations. Continuous use of FAMS over a 2-year period has helped identify its accuracy beyond field data uncertainty. Monthly steady state reports (FAMS vs. field) prepared by the Operations team have shown good agreement between predictions and measurements. Transient conditions such as production shutdowns and hot oil circulation have also been studied and showed good agreement. This has served as means of validation of flowline insulation performance. Code / model limitations have been identified particularly in the area of slug modelling. Integration of FAMS within the BP IT infrastructure and processes have proved challenging as a blueprint for this type of application is yet to be developed. In spite of challenges in this area, the tool uptime and overall health has proved acceptable. Experiences also highlight the importance of clear and rigorous processes for maintenance of the tool between tool provider, IT department and end users, as well as an appropriate allocation of resources with clear roles and responsibilities. Currently there are not many documented cases of use of transient online systems in day to day operations. Experiences described here help demonstrate the value of online transient simulation tools in deepwater environments while highlighting challenges and areas of improvement for this technology. |
