Diffusion in liners in offshore flexible pipes

Flexible high pressure pipes are increasingly used in marine environments for the transportation of well fluids. A flexible pipe consists typically of an inner and outer polymer tube (inner lining and outer sheath), with a number of helically wound steel armour profiles in between. The purpose of the inner lining is to provide the pipe with a leak tight barrier against the transported fluids whereas the outer sheath protects the armour wires from the external environment, e.g. the sea water. A supporting metallic carcass may be applied internally in the pipe bore to increase the collapse strength of the inner lining. The objective of this project is to establish a reliable method for calculating the resulting concentrations of methane, carbon dioxide and hydrogen sulphide in the annulus of flexible high pressure pipes when
subjected to varying operational
conditions.