Life Extension Study of FPSO Systems

Abstract

The objective of this Master Thesis has been to look into the life extension project of the Petrojarl Foinaven FPSO. The Foinaven FPSO has been operating for British Petroleum since 1997 and the objective is to continue production at the Foinaven Field until at least year 2025. The vessel has currently exceeded its lifetime considerably and the life extension project shall execute necessary upgrades and change-outs in order to secure normal operation in the future

In order to provide decision support towards the life extension of the FPSO, Teekay Petrojal has developed a RAM model in order to find main contributors to reduced availability. The thesis gives an overview of the RAM model approach and a presentation of the RAM model results.

In order to support planning for the life extension, a workload analysis has been produced, which gives a yearly workload for the next 6 years. The workload analysis is based on data from Star IPS, the maintenance management system used in Teekay Petrojarl. Star IPS composes a significant amount of scheduled jobs, which are preventive (planned) jobs executed in order to ensure a safe and normal operation of the equipment. The life extension project will cause a high activity level on board the FPSO and the workload results will aid in finding solutions to logistical challenges. The future workload results are compared to the workload history and further discussed.

The process system at the Petrojarl Foinaven has been studied and the manner of operation has been explained. The HP 1st Stage Gas Compressors is a system that, according to the RAM results, will be one of the main contributors to reduced availability in the future. The system has been studied and failure modes have been outlined. In order to secure a successful life extension it will be of great importance to be become familiar with how ageing may introduce potential new failure modes. At last, the maintenance program for the HP 1st Stage Gas Compressor has been studied and discussed. However, the author has found it challenging to identify specific modification or replacement strategies for the system.

The degree of success of the life extension project will be highly dependent on the overall costs. Therefore, a cost prediction approach has been explored in order to see how ageing of equipment will influence the development of the maintenance costs over time. The overview is based on a similar cost prediction approach at the Petrojal Varg, one of the other FPSOs in the Teekay Petrojarl fleet. The approach is described and an example is outlined. Further, a discussion leads to some recommendations regarding how a similar cost prediction approach should be carried out for the Petrojarl Foinaven.