Spool and Pipelay Ovality Checker

Key details

  • Monitoring of critical factors that can shorten life expectancy of assets

  • Dynamic measurement of pipe ovality during pipelay offshore

  • Real-time simultaneous multi-laser measurements

  • Highly accurate and repeatable

  • Traceable measurement results

The systems are flexible and can be modified for a number of deployments as well as having the potential to be integrated and embedded into existing systems.  

Why?

Our customer wanted to understand the ovality induced in the pipe they were laying offshore.

Solution

The solution was to create ring that would surround the pipe but still be capable of being opened via a hinge mechanism to be removed when not being used or for the logistics of the pipelay process. To ensure that the frame was in the centre of the pipe and not affected by boat movements or other effects a larger frame contained the measurement frame. The whole assembly was held in place by wire ropes and by gravity.

As the pipe was being spooled off the vessel lasers on the ring were used to monitor the ovality in real time. An odometer wheel was also used to trigger measurements at any desired interval of movement.

OD ovality checker.jpg

How?

Eight sensors were used to be able to sample the ovality of the pipe. Four would have been sufficient but this would have required accurate rotation of the system to the major or minor axis of the pipe. By taking eight readings there was some redundancy and increased accuracy and it was not essential for the tool to be aligned perfectly.

The ring and lasers were calibrated by insertion of a known diameter and shape calibration ring. Once calibrated, the high repeatability ring could be hinged open and then shut around the pipe.

Each laser’s output was fed into a real time data logger as measurements were available at over 1,000 times per second. The encoder on the odometer was used to select how often to save the data. A rugged laptop was used to record all of the information and store it for subsequent analysis and to present to the operator the current status of the tool or the ovality of the pipe.