Oceaneering AUV-Based Pipeline Survey
AUV-based laser mapping using 2G Robotics’ ULS-500 dynamic laser scanner improves inspection quality while reducing survey time & costs
In 2014, the team at Oceaneering, known for their innovative approach to surveying, was faced with a difficult task: to develop a way to reduce pipeline survey costs while maintaining the quality of the data captured. The team emerged with a simple yet revolutionary plan to perform these surveys using Autonomous Underwater Vehicles (AUVs). With the ability to travel 6 times faster and to host a multitude of sensors, AUVs provided a dynamic platform from which pipeline surveys could be completed in a fraction of the time compared to conventional methods. However, faster vehicle speeds demanded sensors with higher capture rates to ensure high-quality data and resolution.
Oceaneering approached 2G Robotics in an effort to solve their latest challenge. Through substantial levels of collaboration and teamwork, 2G Robotics and Oceaneering were able to develop an optimal solution for sub-centimetric pipeline inspections.
“2G Robotics was able to deliver a best-in-class solution not only because of the quality of their scanners, but also as a result of their ability and willingness to collaborate from an engineering perspective.”
With the aim of delivering unprecedented data, Oceaneering integrated ULS-500s into their fleet of Hugin AUVs; the systems were depth rated to 3000m and equipped with a wideband acoustic positioning transponder, an altimeter, a pressure sensor, an ultra-short baseline system, an inertial navigation system (INS), and a Doppler velocity log (DVL). On average, the operation speed of AUV was 3.0 to 3.5 knots. The calibration of the ULS-500s was completed in an on-shore testing facility and further calibrations were not required for the remainder of the missions.
To execute the survey, three passes were completed along each baseline: one capturing data along the central line of the pipe, with two subsequent passes running along each side of the first pass capturing data about the profile of the pipeline as well as any free spans. This data was then integrated with information captured by the INS, DVL, in order to improve USBL positioning.
The final data was processed to create a seamless mosaic of the survey areas, which was then integrated into a GIS mapping package. This approach allowed the Oceaneering team to compare different data sets and robustly understand the area.
Between 2014 and 2016 Oceaneering completed over 1000 km of laser micro-bathymetric mapping with sub-centimetric resolution using 2G Robotics’ ULS-500. The accepted accuracy was consistently met and in most cases survey lines exceeded the target accuracy.
Accelerated Survey Time
AUVs complete laser micro-bathymetric mapping in a fraction of the time needed for ROV-based surveys.
Improved Operational Efficiency
Less time in the field drives down costs and allows personnel to spend more time on critical analysis.
Detailed Survey Results
3D models with sub-centimetric resolution reveal fine-scale dimensional features not captured by other methods.
Effortless Integration and Calibration
Straightforward integration and calibrations are completed in laboratory saving field time for surveying.