01 Nov 2016
Combination with 3D printing and optical data transmission suggests wider potential in energy industry applications.
Boulder-based company 3D at Depth, which specializes in underwater lidar systems, says that the photonics technology could find wider use in the oil and gas industry, following a project to fix a well head in deep water off the coast of Australia.
In a collaboration with the geosciences and surveying giant Fugro, lidar captured millions of data points that were then used to create a perfect replacement part for the damaged well more than 100 meters under water.
The two companies say that this is the first time that the combination of technologies has been used in this way, and that the success of the project suggests potentially much wider application for cost-effective repairs to high-value infrastructure.
The plugged wells in the completed project were drilled decades ago, and soon abandoned – meaning that accurate data regarding their specification and current state was limited.
Using Fugro's Rem Etive “multi-interventional” boat and its two remotely operated vehicles (ROVs), one was fitted with an SL2 Subsea lidar system manufactured and operated by 3D at Depth.
Mounted on the ROV’s crash bar, the system was able to send reams of data in near-real time to an operator on board Rem Etive, thanks to a multiplexed fibre-optic link between the two vessels.
The survey collected around 44 million lidar data points in 13.5 hours, which were then processed using point-cloud tools to compute spatial relationships, measurements and orientations of the seabed structures.
Those were then converted into a 3D point-cloud database, a dimensional report for each well, CAD files and a 360° animation of each well, and compared with physical measurements collected by the Fugro ROV using different sizes of V-gauges and rulers.
Cross-referencing of the physical and lidar data with the original well drawings then helped identify any discrepancies in existing drawing dimensions.
Avoiding expensive surprises
Adam Lowry, the managing director of 3D at Depth’s operations in Perth, Australia, said: “While the individual sector scans provide millimeter accuracies, the wide-area point-cloud can provide a 3D dataset of centimeter accuracy across an entire drill center.”
He explains that by using the data in advance of any intervention such as a repair mission, expensive “surprises” can be avoided, adding:
"Cost savings can be realized from almost any situation where accurate spatial data would be beneficial to planning intervention operations.”
In this case, the idea had been to use the data to create a full-scale 3D “print” of the top of the well, including its damaged stub. But because the large size of the well cap structure made that prohibitively costly, a combination of 3D printing and CNC machining of the damaged part was proposed instead.
“The first step was to re-process the point-cloud data from the top of the well and then create 3D CAD models of the separate parts,” the project collaborators explain.
However, even this process proved more challenging than imagined, because the shape was so complex. “For this particular part the auto meshing algorithms which convert point-clouds into surfaces did not perform well and as a result the CAD model was developed manually, which is also common when modeling complex shapes from terrestrial laser scans,” they added.
3D at Depth is targeting the oil and gas industry with its technology, and just over a year ago signed a joint development agreement with France-based Technip to expand and commercialize lidar for undersea metrology, field surveys and inspection, repair and maintenance applications.
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