Using a 2G Robotics’ ULS-200, Ocean Atlantic Petroleum was able to fully model an I-Tube as part of a project for a major oil and gas supplier.
Ocean Atlantic Petroleum planned to install a 6” power umbilical through an existing submerged I-tube. In order to do so, they were required to both machine 36 holes into the tube to allow for the proper dispersion of heat generated by the cabling and also assess the current internal state of the asset. This posed a substantial challenge for Ocean Atlantic Petroleum as the confined space of the tube interior limited the approaches they could employ and the level of required accuracy further disqualified many technologies. Historically, such a survey would have been completed using caliper pigging – however these methods suffer from both the inaccuracies of the calipers sensors and operational challenges as a result of the size required for such large tubes. As such, they selected laser scanning for the project as 2G Robotics’ laser scanners offered better than required resolution, while easily operating in the small space available.
The I-tube inspection was performed using 2G Robotics’ ULS-200 underwater laser scanner deployed on a spring actuated pipe centralizer. The laser scanner was lowered down the tube, performing 66 scans, each capturing an approx. 1m section of tube. The goal of the scans was to identify the hole distances from the top of the I-tube, the hole orientation with respect to the pipe centerline and FPSO hull, the expected versus as-surveyed hole locations and orientations and a summary of the inner diameter cross-sections for every 1m of tube.
TThe result of the survey was a complete as-built model of the I-tube. This model illustrated not only the orientation of the holes and the diameter of the pipe, but also the specific characteristics of any identified irregularities. As a result, where anomalies were observed Ocean Atlantic Petroleum was able to further examine them and understand their specific impact on the project. The ability to provide superior resolution and accuracy on the required measurements, while simultaneously providing insight into the general characteristics of the I-tube led the project to be a clear success.