This paper will discuss a past Hydraulic Analysis Limited (HAL) project and the challenges of commissioning a Water Injection (WI) system. The paper will demonstrate how the use of an accurate pipeline simulator which models the full control system can reduce both commissioning time and risk by identifying issues early. The simulator can then be used to modify and tune the control systems prior to and during commissioning.
A computer simulator of a Water Injection system on a Floating Production Storage and Offloading (FPSO) vessel was constructed, including all pipework, pumps and control systems. The simulator was initially used for a design based hydraulic and surge analysis study. During commissioning, the simulator was updated with as-built information and was then used as a commissioning support tool to tune and optimise the various control systems prior to commissioning. All commissioning tests were simulated and assessed before being carried out so that potential issues could be identified and resolved using the simulator.
The simulator identified a number of unforeseen issues associated with the start-up of the hydraulic systems. If these issues had not been identified early then there would have been significant delays to the project. The number of hours expended during commissioning was significantly lower than expected with little ‘fire-fighting’ of problems. The simulator was used on a daily basis to check every commissioning activity via a morning web conference meeting and screen share to run through the simulation results and show the expected pressure and flow readings for that days tests. The expected pressure and flow readings could then be compared to the actual readings during the commissioning tests, ensuring a high level of confidence. By comparing the simulator output to the actual site pressure and flow readings, any unexpected system response was rapidly identified and the system was safely shutdown prior to unacceptable operating conditions occurring. The cause of the problem was then identified and resolved through modifications to the FPSO control systems.