Objectives and goals for the sub project
Investigate Condition Monitoring (CM) techniques for offshore static equipment, namely separators, Safety Critical Valves (SCVs) and Heat Exchangers (H/Xs). Test and evaluate Non-Intrusive Inspection (NII) methods for internal presence detection of offshore production separators, assess suitability of performing frequency analysis of Acoustic Emission (AE) measurement for estimation of valve leakages, and assess important factors around CM that should be considered in the design process of shell-and-tube H/X.

Description of activities and results

• Separators:
  The phase I separator laboratory set-up represents a controlled environment for testing of NII methods for internal presence detection (detection of loose internal components, sand, scale, emulsions, foams, foreign objects etc.). Several tests have been performed, using gamma monitoring, acoustic monitoring and neutron backscatter. Acoustic tests have been performed with varying flow characteristics, using acoustic sensors to detect presence of the inlet cyclone, both with sensors inside instrumentation tubes and on the outside of the vessel. Tests show that acoustic sensors can successfully be used to detect detachment of inlet cyclones. Further tests will follow in 2010.
  
  

Gamma testing has until now been performed against static separator configurations, where separator bottom has been filled with calcium carbonate (for simulation of scale), foreign objects, different kinds of sand and water. In addition interface testing have been performed using gamma monitoring and neutron backscatter, where the separator vessel has been filled with sand, water, emulsions (simulated by high density polyethylene pellets), hydraulic oil, foam (polystyrene) and gas (air). Test results will be further analysed and conclusions will be available by the end of 2009. However, use of gamma monitoring shows very promising initial results with respect to internal presence detection of offshore separators. Also for later tests, where suitability for presence detection of cyclone and baffle plates will be evaluated, the use of gamma monitoring is deemed to be very promising.

• Safety Critical Valves:
  Leak testing has been performed on a 4” ball valve in closed position with different seal damages and corresponding leak rates. This activity involves cooperation with a TAIL-IO PhD and the IO Center. During autumn 2009 frequency analysis for AE signals will be performed and suitability of such with respect to quantification of internal valve leakages will be presented.

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