Gro Stakkestad, manager of subsea intervention and pipeline repair, Equinor, weighs in on her company’s thoughts on subsea resident vehicles.
Why are subsea resident vehicles attractive now?
The recent downturn in the oil price combined with ever increasing environmental awareness forced responsible companies – such as Equinor – to think less conservatively and to investigate cleverer ways to operate. This led to Equinor’s sharpened strategy, including our technology strategy, which among several things sees automation through, as an example, underwater drones as a way to increase safety, lower emissions and decrease cost simultaneously.
At the same time, Equinor observes that there are numerous strong actors developing underwater drones, meaning that there can also be a healthy market with competition and continuous development. However, to maximize competition and development, we see the need for standardization of interfaces. That’s including our subsea docking stations (SDS).
Among the technological drivers there are the recent advanced in artificial intelligence (AI), which is a key technology for tetherless underwater intervention drones. This is due to limitations in range and bandwidth on subsea communication causing limitations – and sometimes preventing – teleoperation by a human pilot. Due to limited assistance from a human pilot, drones need built-in functions to detect anomalies, understand their environment, recognize features and make the right decisions autonomously. This is typically done through AI in the form of artificial neural networks.
What’s Equinor’s vision?
Equinor has never produced cars, but we have built gas stations. We will not produce underwater drones, but we will build charging stations for them on the seabed. We call it subsea docking stations (SDS). Our ambition is that this infrastructure will contribute to a market for underwater drones and our intention is to buy or rent underwater drones developed by others to do inspections and intervention work for us in the near future.
Equinor’s vision is that all major tetherless vehicles with hovering capability will be compatible with our SDS. Hovering drones are more agile than traditional ROVs, making them capable of station keeping, autonomous intervention with torque tools etc., and docking onto a flat standardized “helipad” – the SDS.
There are several alternatives, and I envisage these will happen in steps as the technology matures. Let me give some examples. With a standardized docking station and network solution, we can have several types of drones in the same field and do adjustments to the drone fleet as technology progresses. Depending “on a case-by-case basis” of the particular tasks (e.g. inspection, intervention, environmental monitoring), we will make specific business cases and determine the type(s), numbers and density of the docking stations. The setup may vary quite much field by field. If we can combine drones over several fields – “inter-field operations” – this will strengthen the individual business cases further. Some of the drones have relatively high range, in excess of 100 kilometers (for example Oceaneering’s Freedom), so in some cases it can travel between fields. We are also looking into the use of unmanned surface vessels (USV) which could be used to deploy drones to remote locations (as a mother ship), but this could also be used to transport drones between locations, if the distance between the SDS are too large.
What is being done now?
The SDS in Trondheimsfjorden is permanently installed at 365 meters depth, and available for test and research activities thru NTNU (Norwegian University of Science and Technology). We plan to install a similar docking station at the Åsgard Field, and more docking stations in the years to come.
(An evaluation of the potential use of UID on the Snorre field is ongoing. A final decision is expected to be taken later this year).