TABLE OF CONTENTS Expansion may be induced by internal pressure and temperature. In recent years, more and more High Pressure and High Temperature (HP/HT) fields are developed using pipelines and steel catenary risers. In this design scenario, axial creeping, buckling in the form of upheaval movements and lateral movements or a combination of both, may take place.
In this Chapter, the basis for expansion analysis will be outlined first with a focus on effective force calculation. An analysis model is introduced for axial creeping of a high temperature flowline in clay soil condition. Simplified mathematical equations are presented for use in the upheaval buckling and lateral buckling designs. Finally HP/HT flowlines will be considered on uneven seabed, and their buckling behavior will be characterized as a combination of upheaval and lateral buckling modes: the flowline will uplift first and then move more laterally. There are many papers published on these subjects. Hence, we shall focus on the mathematical formulation that has actually been adopted in the current pipeline design practice. Some further readings include Ellinas et al. (1990), Kershenbaum et al. (1996), Nes et al. (1996) and etc.
A pipeline can be a single or piggybacked pipeline system, pipe-in pipe or bundled system. Its expansion is dependent on the temperature, pressure profile, pipeline self weight and friction forces. The expansion analysis will interface with:
Tie-in Design;
Lateral and Upheaval Buckling Assessment;
Free-span Assessment;
Crossing Design;
Bottom Roughness/ Stress Assessment.
The maximum pipeline end expansion is calculated...
