The Problems Associated with NDT of High Pressure Flexible Pipes

Abstract

The variety of materials used in the manufacture of high pressure flexible pipes provides, in the first instance, an extensive range of possible NDT methods. However their complex, composite construction imposes equally extensive constraints on the operability and potential effectiveness of many of these methods.

Additionally, little detailed information is available on actual failure modes of flexible pipes and data from examinations of failed pipes is largely confidential to individual operators.

Ageing of non-metallic components presents a particular problem since nearly all of the common tests for determination of material properties are of a destructive nature.

In addition to the complex construction further constraints on in-service inspection are imposed by the presence of bend restrictors, anode bracelets, and buoyancy elements on risers, by the burial of flowlines, and by encasement in J-tubes.

This paper addresses some of the problems of inspection and monitoring flexible pipes and describes some of the methods which are currently being considered as potential solutions to them.