Exploration • Drilling • Field Services
measurement data, if used in the correct way, can then help to ensure that pipes delivered into the bead stall will fit together within the specification requirements for welding. Typically, end dimensioning and fit-up involves two main steps: measuring and fit-up. Te measuring stage involves the actual collection of pipe measurement data. Here, automatic, laser-based measurement tools can be used to measure the geometrical features of pipe ends, normally performed onshore, although this process sometimes needs to occur on a cargo barge.
Laser-based measurement tools can be used to
measure the IDs and WTs of pipe ends in rapid time. Typically, several thousand IDs of a pipe can be measured in less than half a minute, enabling hundreds of pipe ends to be measured in a single shift. Tis means less time on site, minimising project delays and costs for the pipelay contractor
Data from laser-based measurement tools can be made available to pipe optimisation software, which will include some sort of simulation or sequencing software, as is included in OMS’ SmartFit program. Tis software uses pipe measurement data to predict and control the fit-up, before the pipes are brought into the bead stall for welding. Tis 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. Te 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 1.0 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 HiLo’s 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 1.0mm, problem fits will occur in 20 to 50 per cent of the cases.
Fig. 2. In the bead stall, datum marks are aligned to immediately achieve best rotational position so that pipe end misalignment is minimised..
Laser-based measurement tools are also very accurate (typically to 0.05mm). Using tools such as these saves a lot of time.
Being able to measure up to 400 pipe ends in a single day is at least three times faster than using regular, conventional measurement tools (eg caliper gauges), which only measure at a few discrete locations around the pipe. Pipelay contractors are therefore able to keep
their project schedules on track and because some projects involve measuring more than 2,500 pipes, the time and cost savings are significant.
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www.engineerlive.com 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
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