Condition Monitoring and Opportunity Maintenance in Offshore Operations

Abstract

In this M.Sc. thesis organisational and technical aspects related to the implementation of an Opportunity Based Maintenance (OBM) scheme for Oil and Gas facilities have been discussed. Organisational aspects of importance include agility and resilience. Agility can be understood as the ability of organisation to benefit from unexpected events. Resilience can be understood as damage control. Logistics support elements from the space industry can also be beneficial to implement in the logistics support of Oil and Gas facilities. Elements from the space industry include the implementation of Onshore Support Centre (OSC), prepositioning of spares and tools and standard procedures for critical equipment.

A simplified oil and gas production system has been used as a basis for a Failure Mode Effects and Criticality Analysis (FMECA), identifying critical components that should be considered for Condition Monitoring (CM). The results of the FMECA were that centrifugal compressors and shell and tube heat exchangers were ranked as critical equipment. Gate valves were also ranked as critical but have been neglected in the further analysis due to heat exchangers and compressors being more critical.

Several different CM methods have been described, emphasis have been put on detection method, application and words of warning when implementing the method. CM methods relevant to the critical equipment have also been discussed. For compressors the most relevant CM methods includes Vibration monitoring, Power and Load monitoring. In addition to these general methods special software applications are also available through different distributors. For monitoring heat exchangers internal inspection is most commonly used. The inspection interval can be determined by a Risk Based Inspection (RBI) scheme. When an inspection is due Eddy Current Testing (ECT) or gas leak tests can be used to determine diminishing pipe thickness in the tube section of the heat exchanger. HXAM supplied by ABB is also an interesting solution offering real time measurement of the performance of the heat exchangers.

Lastly how logistics planning is related to maintenance of oil and gas facilities today have been discussed. How a shift to OBM will impact the logistics planning have also been discussed. Means that can reduce any negative impact that a shift to OBM may have has also been discussed. One such measure is the investment in a fully automated warehouse. Also lessons that can be learnt from the logistics support in the space industry have been emphasised again.