Technical Presentations at the April 2011 Meeting
CAPCIS has developed corrosion fatigue testing facilities to determine
the behaviour of armour wires used to give strength to flexible flowlines
in both production and water injection flowlines.
The purpose of fatigue testing is to determine the fatigue properties of
the pressure armour and tensile armour wires located in the annulus of
flexible pipelines. The
results are used by the client in collaboration with full scale testing to
make service life predictions of flexible lines. The result from a
corrosion fatigue test is an S-N Curve (stress range plotted against the
log of the number of cycles to failure).
currently has 12 fatigue rigs set up at its Trafford Park Testing
Corrosion fatigue testing is carried out in environments specified by
the client (flexible pipeline manufacturer) according to the end users
requirements. Information on well fluids, pressure and temperature
conditions are supplied by the end user to the manufacturer. The manufacturer then carries out permeation calculations and
environment predictions and specifies the environment to CAPCIS to carry
out the corrosion fatigue testing. Typical environments include,
Saturation of the aqueous environment with a gas mixture simulates
permeation of gases from the bore into the annulus of the pipe.
Testing in aerated seawater simulates rupture of the outer sheath.
‘Optimization of Retrofit CP Systems using Mathematical
Modeling by Evaluating Performance of Remnant and Retrofit CP Systems,
Taking into Account Long-term Polarization Effects’, John Baynham,
Installation of retrofit
sacrificial anode CP systems to aging structures is routinely performed to
provide life extension of offshore assets in matured fields.
Sometimes earlier retrofit systems are now being replaced or
It is important to
understand when the remains of previous CP systems can no longer prevent
depolarization, because timely intervention can reduce overall retrofit
cost. Life of the new CP
system must be some required number of years, and ideally the design
should take into account performance of any remaining anodes and the state
of calcareous deposits on the structure.
Data which can be used to help identify the state of calcareous
deposits and remaining anode mass is generally available from past
During design of a
retrofit system, simulation can be used firstly to gain quantitative
understanding of the state of the structure, remaining life of existing
anodes and estimated date at which serious loss of calcareous deposits
will occur. Secondly, it can
determine the short-term effect of a new CP system on structural
potentials. This information can be used to modify the numbers, positions
and mass of new anodes in a revised design.
This process optimizes distribution of potential and anode mass
The same techniques can be
used to weigh up the benefits of fewer large versus several smaller
Finally, simulation can be
used to determine the long-term effects of new, old, and combined CP
systems, for example to identify when individual anodes reach their
utilization factor and the consequent effect on the remainder of the
pdf version of this presentation has kindly been provided for staff of MCF
member companies – please contact the Secretariat for a copy
1.3 ‘Is There Value in Translating New Wireless Corrosion
Monitoring Technologies to Upstream Oil and Gas?’, Adrian Bowles,
Recent years have seen an
increase in the commercial availability of advanced corrosion monitoring
systems that promise greater convenience and the provision of improved
quality data. This
presentation will be a brief overview of these advanced monitoring
techniques and the advantages they can bring over more traditional methods
of monitoring corrosion.
The first half of the
presentation will review the deficiencies of traditional corrosion
monitoring techniques before putting forward criteria for the perfect
technology. Eight of the most
advanced permanently installed corrosion monitoring systems will then be
evaluated against these criteria.
A limited number of corrosion monitoring technologies offer a wireless data transmission solution to reduce the costs of installing cabling and performing manual interrogation. Industrial facilities are harsh environments for radio frequency communication and the second half of the presentation will explore reliable wireless technologies designed to operate in heavy industry and the unique challenges that may be presented by upstream oil and gas facilities. Finally, traditional and advanced corrosion monitoring techniques will be compared using data from manual ultrasonic measurements and an automated, wireless, permanently installed system to illustrate the value a wireless corrosion monitoring technology could bring. [[email protected]]
This presentation started by providing definitions for both corrosion engineering and corrosion management in the oil and gas industry and then focused on the ten corrosion management products which if are missing or are not applied properly, could adversely affect the overall integrity management (of the associated pressure systems) of an offshore asset. All discussions were based on past cases encountered either in the UK’s North Sea Sector or elsewhere. [[email protected]]
A pdf version of this presentation has kindly been provided for staff of MCF member companies – please contact the Secretariat for a copy.
It has long been understood that the heat treatment of duplex and superduplex stainless steels is critical to obtain the optimum structure and the desired properties. Over the last twenty years there have been a number of cases where inadequately heat treated components have been delivered by the manufacturer and then subsequently identified as defective further down the supply chain. In some cases the problem was identified and resolved prior to fabrication and installation, in others fittings have leaked in service due to poor microstructure from incorrect heat treatment.
Common to all these cases is that the cast and batch production test certificate indicated that the goods met specification requirements in all respects. Hence the similitude between cast and batch specific test pieces and the production parts has been called into question. There has been extensive discussion on how best to test individual components non-destructively to detect unsatisfactory material. Some have suggested that magnetic measurement of the ferrite content is adequate, whilst others believe the test to be insufficiently discerning, resulting in too many good parts falsely being identified as “suspect” and causing unnecessary remedial action. Various electrochemical tests to assess individual item quality have also been proposed.
The present paper described the strengths and limitations of magnetic ferrite measurements and showed how the readings are affected by manufacturing route, product form, surface roughness and radius of curvature. The paper went on to show how the test can be used to identify material that may contain sigma phase and that in-situ metallography is then required on these suspect areas to either release the part or condemn the part to remedial heat treatment. The results of five years successful experience with this combination of tests was discussed.