Prior to modification works on the hull of an FPSO, a North Sea operator identified a need to plug two open ‘seatubes’ in order that modification works could be conducted on the water handling system. With no original CAD or drawings of the item available, the client required a 3D scan of the area to help with the design of the plugs
The near 90-degree bend immediately inboard of the seatube opening had not been documented, meaning the customer was also unaware of how far into the seatube any plug could be inserted before the bend was reached.
As a result, it was not immediately apparent how an ROV might approach the work site whilst achieving the necessary angles for correct cleaning and image capture.
The capture was planned and executed remotely, whereby the imaging equipment was issued to the marine contractor, alongside a guidance procedure and 3D guidance animation.
A virtual meeting walked the ROV team through the operation, highlighting best-practice in terms of collecting technically valuable 3D geometry.
Changes were also made to the method by which the ROV held and manipulated the cleaning and image capture equipment, so as to address the challenging angle on the bottom of the vessel hull.
The data was then reconstructed in 3D. As well as a standard geometric analysis reporting, Viewport3 also provided angular (pitch and yaw) information, due to the pipework not being perpendicular to the seatube opening.
On completion of the 3D reconstruction, the data was subjected to 3D point cloud analysis and reverse engineering to the satisfaction of the customer. The design and manufacture of the temporary plugs proceeded and was followed by a successful and efficient installation campaign.
