Atlantic and Cromarty – A Hydrate Blockage and Remediation Case Study

This paper describes the initial identification and characterisation of a hydrate blockage that formed in the main 80 km pipeline that transports gas and condensate production from the Atlantic and Cromarty fields in the UK North Sea. During the gradual depressurisation of the pipeline to remove the hydrate plug, unexpected pressure pulses were observed at the offshore end of the pipeline that were consistent with movement of hydrates. It was then determined that the risk of damage from further hydrate movements would be acceptably low before further depressurisation could take place to remove the accumulation of hydrate.