Drones arrive on Slope
FAA OKs use of unmanned aircraft for mapping and surveying at Prudhoe Bay
The Federal Aviation Administration has authorized BP to use unmanned aircraft systems for surveying operations in the Prudhoe Bay oil field on Alaska’s North Slope, the first time that the agency has approved the use of unmanned aircraft over land in the United States. The aircraft, sometimes referred to as drones, are equipped with laser-based surveying technology called LIDAR, for making high-precision measurements of surface features, including roads and pipeline structures.
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“These surveys on Alaska’s North Slope are another important step toward broader commercial use of unmanned aircraft,” said Transportation Secretary Anthony Foxx on June 10 when announcing the issuance of the drone authorization to BP. “The technology is quickly changing, and the opportunities are growing.”
The FAA says that the approved type of aircraft is a Puma AE, a hand-launched, unmanned vehicle about 4 1/2 feet long and with a wingspan of 9 feet.
BP says that it wants to use the drones for high-accuracy surveying and mapping.
Road surveysCurt Smith, technology director with BP’s Chief Technology Office in Houston, told Petroleum News that the machines have an immediate application in developing high-precision surface maps of the gravel roads at Prudhoe Bay. A conventional aircraft has to fly at a height and speed that limits the accuracy of the LIDAR data, Smith explained. But a small drone, with a cruise speed of perhaps 25 miles per hour at an altitude of just 150 feet, can potentially achieve a survey accuracy of 5 centimeters horizontally and 1 centimeter vertically, he said.
And that level of accuracy in road surveying can feed through to improved road maintenance, a critical factor in Prudhoe Bay field operations. Any discrepancy from required specifications for a gravel road surface can lead to problems with operations such as the movement of massive drilling rigs between different oilfield sites, Smith said. A road blockage caused, for example, by a rig becoming stuck, can become an expensive and time-consuming problem.
GPS guided gradersSmith said that BP is starting to use GPS-guided road graders to improve maintenance efficiency. The grader has a screen that guides the driver of the machine, ensuring that the grader follows the road’s centerline, he said. A ground-based GPS correction system enables a GPS receiver to achieve a positional accuracy of 5 centimeters, he said.
But this high level of positional accuracy is of limited value without equally accurate maps. And that is where the high-precision mapping from the LIDAR-equipped drones comes into play, with the plotting of the precise location, shape and profile of each Prudhoe Bay road. Now, a grader equipped with a precision GPS receiver at each end of its blade, can be programmed with data describing both the actual road profile and the required road profile, enabling the precise adjustment of a grading operation, Smith said.
GPS technology can also provide the means to steer graders along the roads during periods of low visibility. And BP is considering equipping drilling rigs with GPS systems, thus, in combination with a high precision map, enabling a rig to be accurately steered along a road centerline, avoiding the risk of the rig crossing the edge of the road, Smith said.
More new ideasAnd, as with many emerging technologies, the successful operation of the drones is rapidly spawning a series of new ideas for their use.
“It’s going to be a big deal,” Smith said.
For example, having seen what the drones can achieve in terms of road maintenance, pipeline maintenance staff are using the drones to survey the Prudhoe Bay pipelines, thus greatly increasing the efficiency and frequency of the survey operations required to detect problems such as frost heaves that can cause pipeline support members to move, Smith said.
BP has also used the drones to measure the precise volume of gravel obtained from a state gravel pit, he said. Other ideas include the mapping of culverts, to identify improved culvert locations, and the aerial inspection of equipment such as tanks and electrical lines.
Safe operationBut what about the risk of a mid-air collision, given the fact that the aircraft are unmanned?
BP notifies the local air traffic control services before any drone operation, with the air traffic controllers then notifying aircraft of what is happening, Smith said. The operators of the drones also use radios to keep other aircraft informed about the drone flights, he said.
Being in the air, the drones do not disturb the tundra. And, having electric motors, the vehicles create no discernible sound when flying, Smith said.
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