Internal Pipe Inspections Over the past decade, customers have relied on 2G Robotics underwater laser scanners for interior pipe inspections. The interiors of pipes, i-tubes, j-tubes, caissons, piles, wells, and tunnels ranging from 0.5m to 6m inner diameter have been inspected with the correct 2G Robotics product deployed with bespoke deployment methods. From as-built validation, buckled pipe ovality measurement, to anomaly inspection, 2G Robotics has the right tool and method for the job. A few example deployment approaches have all been used to deploy 2G Robotics underwater laser scanners to achieve unmatched inspection precision inside pipes.
Gravity Frame A centralizer frame is a wheeled scissoring system that maintains pressure against the pipe walls while being lowered into the pipe. With the laser scanner mounted to the end of the apparatus, it remains relatively centered and aligned within the pipe. By keeping the laser scanner centered in the pipe, equal coverage of the pipe is captured all around, minimizing the number of setups needed to achieve complete coverage and also maintaining equal data densities all around. One example of the use of a gravity frame was by Ocean Atlantic Petroleum who used a ULS-200 to inspect a 44” inner diameter I-tube on an FPSO in Angola. The objective was to obtain as-built geometry of the I-tube to ensure unobstructed installation of a 6” power umbilical through the tube. The ULS-200 was deployed inside the I-tube using a custom designed spring actuated pipe centralizer. By lowering the centralizer frame at predetermined intervals, the ULS-200 captured high resolution true-scale point clouds of 360 degree segments of the i-tube inner diameter. The centralizer deployment frame and point cloud result are shown below. These point clouds sections were then merged to provide a complete final result.
A second example of a gravity frame that was not using a centralizer is during an offshore wind farm installation in the Baltic Sea following a 2.6m inner diameter pile becoming damaged during the pile hammering procedure. The depth and extent of the damage was unknown to the installers. 2G Robotics ULS-200 underwater laser scanner was called upon to determine the depth and extent of the damage to the buckled pile. Due to the size of the pile, a unique solution to deploy the laser scanner into the pile was engineered. The ULS-200 was attached to the large pile cutting tool that was readily available on survey vessel. The cutting tool was paid out at intervals of 0.5m through the pile allowing the ULS-200 to rotate 360 degrees at each interval. To precisely determine the position and orientation of each laser scan, the cutting tool was outfitted with a depth sensor and 3-axis subsea gyro. A point cloud model was generated and numerous slices of the inner diameter were processed and measured. The inspection of the buckled pile was seamless and successful; the end client proceeded to use the technique as an as-built verification on other piles.
A swath of damaged subsea pipe captured with a ULS-200.
Ovality measurements of a damaged underwater pipe segment.
Tracked Crawler Deployment The ULS-100 / 200 and 500 have all been integrated into tracked crawler vehicles for scanning inside of pipes and tunnels. Tracked crawlers provide highly stable platforms necessary for high accuracy underwater profiling. These tracked vehicles depending on their track configuration climb vertically, dealing with complicated and challenging pipe geometry. For long tunnel penetration inspections, the laser scanner can be supplied power by the auxiliary power from the vehicle and can be integrated through the vehicle’s multiplexer maintaining only the single cable from the surface to the vehicle. In this example, a ULS-100 was integrated to a horizontal Inuktun crawler in order to inspect the unions between raw water pipe segments. During installation of new pipes, the alignment of pipe joints is critical to overall pipeline integrity. Using the crawler’s forward facing camera, the crawler was navigated to joint locations between pipe segments where the ULS-100 was allowed to capture a 360 degree point cloud. The ULS-100 point cloud results provided true-scale measurements of the union gaps which traditional cctv inspections were unable to measure. Center axis alignment from segment to segment was also measured to ensure alignment tolerances were achieved. Inner diameter deviation and anomaly identification were also side benefits to the laser operation.
A second example on another Inuktun vehicle was when IPI Group inspected the raw water intake tunnel for the city of Bellingham. This tunnel needed to undergo routine inspection operations and a combination of video and laser scan data was collected to assess the integrity of the tunnel. The Laser Scanner and crawler was deployed into multiple access points along the length of the tunnel to achieve coverage over the multi kilometer tunnel.
ROV Deployment Integration with ROVs is similar to integration with crawling vehicles. The difference is that where crawlers can be more easily stabilized for collecting scans, ROVs have increased maneuverability. This increased maneuverability can be highly beneficial in cases where there is debris or other obstacles inside of the pipe. AUS-ROV, an Australian underwater inspection company is using their ULS-100 for internal pipe and tunnel inspection. With the scanner integrated on a custom bracket to their Seabotix LBV, the system collects data at stages along the length of tunnels. The vehicle maneuvers into the desired scan location and then sets down to remain stable during the scan before then lifting off again to the next scan location.