Case Study

Storage tank inspection for Equinor at Mongstad refinery

Drone inspection with live streaming was performed using the Scout137 Drone System and the Scout Portal at Equinor’s Mongstad refinery in Norway.
Oil and Gas | Tank Storage

A live drone inspection of a large bulk liquid storage tank was performed in front of an on-site audience at Equinor’s facilities in Mongstad, Norway.

The inspection was live-streamed to remote stakeholders who watched the inspection in the Scout Portal and guided the on-site inspection crew. Concluding the project, a Scout 137 Drone System was delivered to Equinor.

Time Savings

Reduced asset down-time through flexible inspection regimes

Cost savings

Reduced cost by avoiding scaffolding, climbers and rescue teams


​Improved safety by reducing need to enter hazardous areas


Improved data quality and situational awareness in data capture


Equinor ASA is a Norwegian state-owned multinational energy company headquartered in Stavanger, Norway. It is primarily a petroleum company, operating in 36 countries with additional investments in renewable energy.

Mongstad is an industrial site in Vestland county, Norway. Equinor’s involvement in Mongstad now includes an oil refinery, an NGL processing plant, a crude oil terminal, a cogeneration plant and the world’s largest technology centre for CO2 capture from flue gas. 

Mongstad refinery from the air

Mongstad refinery site

On-site at Mongstad

The scope of the Mongstad mission was to deploy the Scout 137 drone system and perform an inspection inside a cylindrical tank. Further, an inspection would be performed to demonstrate the current capabilities of the drone system itself, as well as the remote inspection capabilities enabled via the Scout Portal.

Three flights were conducted with full line-of-sight, i.e. the drone operator and other bystanders were present inside the tank. This was a newly built tank and equipment was present that is not expected during a typical inspection: Scaffolding, ropes hanging across the open area, and a painting robot set up for testing. There was also a temporary, raised platform of scaffolding in the middle, where the drone started and ended each flight.

Scout 137 inspecting paint quality, Equinor

Scout 137 inspecting paint quality, picture from Equinor.

Drone inspection in a new structure before it is put to real use can be very useful to check beams, bolting and other things. The Scout 137 Drone also performed a quick inspection of the paint quality from the installed paint robot.

While the drone was flown manually in this case, it has slide-along-wall functionality that keeps a fixed distance to the wall. This is very useful when inspecting large surfaces that have a slight curvature; without this wall-following function the operator would have to perform a slight rotation continually while also sliding sideways. A difficult task, which would also produce much more uneven and variable video data than what is the case now.

Photo of tank wall with blue paint, interior

Screenshot from Scout 137 Drone inspection footage, Mongstad.

When operating from inside the tank, the metal structure can disrupt wireless radio signals. Therefore, an Ethernet cable was plugged in to connect the drone controller to the ground station, which in turn connected to the Scout 137 Drone via the tether.

This eliminated the risk of control signal loss during the inspection flights. In addition, having the ground station outside the tank, allowed it to maintain an internet connection for live-streaming the inspection to the Scout Portal.

For the inspection, the ground station was connected to the internet via the built-in 4G modem. Alternatively, an Ethernet connection can be used for connection to the Scout Portal through local internet ports or a Wi-Fi router. More about the Scout Portal, below.

Overall, the Mongstad missions were a success. The on-site Equinor team supported the operation and all local requirements were taken care of. The drone was easily deployed to perform the flights necessary to gather data with a minimum of on-site preparation.

Interior of large storage tank

Screenshot from Scout 137 Drone inspection footage, Mongstad.

Location-tagged inspection data and situational awareness

A key advantage of the Scout 137 Drone System is that the inspection data is location-tagged. Algorithms for simultaneous localization and mapping based on data from the onboard 3D Lidar is used to create a 3D map in the form of a point cloud of the asset. In addition, the position and attitude of the drone is estimated at every point in time. This means that, at any time, you are able to see where the drone is and where it’s headed; live while flying or in post while reviewing the inspection data.

The Lidar-based 3D map is displayed on the drone operator’s information tablet. Using this, they can see the camera feed as well as the 3D map to understand where the drone is located and headed inside the inspection target. The map can be zoomed, panned, and rotated freely.

This is of tremendous help, especially of course in a non-entry situation where the operator has no line-of-sight to the drone from where she’s standing.

Tablet with on-screen 3D map and video frame
Scout Tablet screenshot before take-off at Mongstad. Lidar scan clearly shows the tank circumference as an point cloud. Minimized video feed in the bottom left corner. Picture from Equinor.

The Scout Portal