Inspection surveys are performed to assess the integrity of pipelines and flowlines. Formerly performed with Remotely Operated Vehicles (ROVs), deepwater pipeline inspection surveys are now being accomplished with Autonomous Underwater Vehicles (AUVs).
AUVs provide higher quality deepwater pipeline inspection data than an ROV and do it faster and more cost-effectively.
C & C’s standard AUV sensor suite includes side scan sonar, multibeam bathymetry, and sub-bottom profiler. The C-Surveyor VI pipeline inspection AUV is integrated with additional state-of-the-art sensors. These include a bathymetric 3-D laser, a camera photo mosaic system, and a magnetometer.
The bathymetric 3-D laser provides a three-dimensional, engineering quality, "point cloud of data” to detail critical subsea infrastructure including pipelines, mats, sleepers, collars, and the surrounding environment. Subsea engineers utilize the high-density 3-D point cloud data to identify and measure pipeline displacements, deformations, spans, anodes, and top-of-pipe to a resolution of five millimeters.
The AUV camera photo mosaicing system simultaneously collects calibrated and geo-referenced high resolution images every 1.75 seconds. It produces a visual record of subsea infrastructure, identifies targets, and corroborates anomalies detected with other AUV sensors. These images are processed into geo-referenced photo mosaics and pseudo video files. Photomosaics offer several advantages over video files, which are time-consuming and tedious to review. Geo-referenced photomosaics are automatically generated and provide the user with rapid view, zoom, and search capabilities.
An integrated magnetometer measures variations in the earth’s magnetic field and detects ferrous objects. This system was originally developed for down-hole directional drilling applications and is perfectly suited for deepwater AUV operations. The magnetometer detects pipelines and undersea cables, maps geophysical anomalies, unexploded ordinance, and archaeological sites; and can be correlated with other sensor data for target identification purposes.
Watch the video of C & C's C-Surveyor VI pipeline inspection AUV.