Riser/ Pipeline Accidents

Riser/pipeline accidents can have severe topside consequences. An export riser or pipeline rupture can result in gas leakage rates of several thousand kilos per second. Riser ruptures or large leakages may result in strong explosions and/or intense fires and possible loss of platform. Pipeline ruptures or large leakages, away from platforms, may expose third party on merchant ships or settlements onshore. A very large subsea gas leak will result in strong currents and high void fraction at the surface which may sink ships and boats due to strong list.

Riser/pipeline accidents can have severe topside consequences. An export riser or pipeline rupture can result in gas leakage rates of several thousand kilos per second. Riser ruptures or large leakages may result in strong explosions and/or intense fires and possible loss of platform. Pipeline ruptures or large leakages, away from platforms, may expose third party on merchant ships or settlements onshore. A very large subsea gas leak will result in strong currents and high void fraction at the surface which may sink ships and boats due to strong list.

Factors leading to riser accidents may be:

• ship collisions
• dropped objects
• vibrations due to subsea currents
• over-pressuring
• explosion or fire exposure.
• platform drift

Factors leading to pipeline accidents may be:

• fatigue due to free spans
• impact from trawl boards
• landslides
• earthquakes
• anchoring
• sinking ships
• internal or external corrosion
• over-pressuring
• valve collapse
• mines

Scandpower usually use Olga in order to evaluate pipeline/riser accident scenarios, i.e. leakage flow rates and durations. Olga is a world leading commercial multiphase flow simulator for pipeline systems. Accident probabilities are estimated through analysis.

This analysis incorporates failure frequencies from statistical databases which are relevant for the specific type of pipeline or riser. This in combination with the consequence analysis gives the total risk contribution to the platform, floating production vessels or third party. Based on this information, risk reducing actions can be taken if necessary.