This paper describes two advances in the pipefreezing technology, now available to offshore installation operators. Flexible vacuum insulated liquid nitrogen transfer lines may now be used to feed freeze jackets located in inaccessible places and to improve the security of coolant supply generally. The development of the heat flux monitoring system allows the progress of a freeze to be followed, close-off of the plug confirmed and the condition of the plug to be monitored. The practical application of both these new developments is illustrated with examples.

Keywords:
transfer line, society of petroleum engineers, freezing, hose, freeze site, heat flux, unattended hold time, application, vacuum, liquid nitrogen
Subjects:
Pipelines, Flowlines and Risers
Copyright 1991, Society of Petroleum Engineers
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