New Design Challenges
in Marginal Fields
The feasibility of constructing pipelines to transport
high temperature and pressure contents has become central
to the development of marginal fields. Pipeline systems
with fluid temperatures of 160°C or more have been
and are currently being designed.
At temperatures above about 120°C several factors
become primary which are not significant for pipelines
transporting lower temperature contents. These factors
include:
• The effect of elevated temperatures on the mechanical
properties of the pipeline steel, including carbon steel,
corrosion resistant alloys (CRA) and CRA lined carbon
steel pipe.
• Practical problems of designing pipeline systems
that conform to current codes based on limiting stress
conditions and the relevance of limit state codes to
high temperature pipelines.
• The requirement to adopt a strain-based design
methodology. The adjective “strain-based”
is used here to describe pipelines where the traditional
limit on the equivalent stress in the pipeline is replaced
by a limit on the strain experienced by the material.
These factors must be resolved in order to ensure that
HPHT pipelines can be operated with suitable levels
of safety.
HPHT Design Experience
Since its inception, KW Ltd has been in the forefront
of HPHT pipeline technology. Our work has ranged from
conceptual design through to development of detailed
design and assessment of operating pipelines.
To provide a sound technical base for these activities,
KW has been involved in Research and Development via
JIPs, extensive testing, technical development and input
to guidelines and standards.
Technical Capability
• Detailed analysis of single pipe and pipe-in-pipe
systems transporting high temperature and/or high pressure,
including interaction with HIPPS.
• Detailed Finite Element analysis and design
of pipelines susceptible to Lateral Buckling.
• Limit State and Strain Based Analysis and Assessment,
including analysis of cyclic loading conditions and
fatigue limit states.
• Experience of Trenching and Burial of Pipelines,
including expertise in incorporating the effects of
strain based analysis into the upheaval buckling calculations.
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