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Tube Products International March 2013
Optical Metrology Services Ltd
– UK
in OMS’s SmartFit
TM
program. This software uses pipe
measurement data to predict and control the fit-up, before the
pipes are brought into the bead stall for welding.
This can avert production issues relating to poor fit-up and
manages the assembly of problem pipes in order to maximise
welding productivity.
Measure, mark and fit-up
Each pipe end is measured, identified and entered into the
software. The software analyses the fit-up of pipes and allows
the operator to mark the best rotational position on each pipe
end. In the bead stall, these marks are aligned to immediately
achieve the best rotational position so that misalignment is
minimised.
Any problem pipes that won’t fit at a specified HiLo are also
indicated and are re-sequenced or removed completely so
that fit-up problems do not occur in the bead stall. Production
delays due to mismatched pipes are avoided.
Experience shows that with typical flowline HiLo limits
and using typical seamless line pipe that has not been
counterbored, fit-up issues can occur regularly depending on
the HiLo requirement.
For a HiLo of around 1 to 1.2mm, problems are likely to occur
every 10 to 20 pipes (this varies according to the exact project
and the type of pipe).
Using pipe optimisation and simulation software enables the
required HiLos to be achieved in the bead stall without trial
and error. But when pipes will not fit, this will be indicated
and the problem pipe can be taken out of sequence, therefore
avoiding any problems in the bead stall. For a HiLo of 0.8 to
1mm, problem fits will occur in 20 to 50 per cent of the cases.
Many pipelay contractors are benefiting from working closely
with experienced, independent measurement specialists such
as OMS, helping them to avoid a range of potential issues
such as wall thickness problems in SCR and flowline pipe,
counterboring of SCR pipes and poor fit up on board ‘J-lay’
vessels.
OMS has already completed more than 30 major projects
with customers using its SmartFit software, which optimises
pipe fit-up and HiLo. SmartFit comprises a laptop computer
system used prior to the pipe firing line, for example, in a
‘ready rack’ on the pipelaying vessel.
In one particular pipe fit-up project, OMS project managed
the complete pipe measurement, mark up and fit-up process,
both onshore and offshore.
After the pipes were measured onshore and marked up,
they were transported by cargo barge to the laybarge. Using
cranes, measured pipes were offloaded in small batches of
15-20 pipes to a pipe holding area on the main deck of the
laybarge.
Here, an OMS inspector noted down the pipe numbers of the
stack, creating a visual representation of the physical position,
number and end designator of the pipes and whether any
were ‘anode’ pipes.
Using SmartFit, the pipes were sequenced to obtain best fit-
up. The pipes were then numbered for the riggers.
The riggers loaded the sorted pipes in the correct sequence
to the pipe bevelling inbound rack. After bevelling, OMS
inspectors marked up the pipes with rotation and datum
marks.
The spacer crew were then able to correctly align these
rotation marks, which minimised the HiLo. This ensured that
the project HiLo specification was met and that welding
problems were avoided prior to the firing line.
About Optical Metrology Services
Optical Metrology Services Limited (OMS) provides pipe
measuring products and services, specialising in measuring
equipment and consulting services for use within the pipe
manufacturing and pipeline construction sectors, both
onshore and offshore.
A key focus for OMS is the dimensional measurement of oil
and gas pipes or other structures such as military gun barrels,
processing industry tubes or manufactured cylindrical objects,
where dimensions are critical.
