Remote offshore facility inspection
31 October 2013
Falls from height remain the leading cause of fatalities at industrial inspection sites. Tall and inaccessible structures such as flares and chimney stacks need to be accessed regularly as part of visual and thermal inspections.
Such inspections are not without problems; they can not only be expensive and time-consuming, but also potentially dangerous, as they involve personnel working at height or near hot surfaces.
A Cyberhawk ROAV - Photos: Cyberhawk
It can all add up to putting a facility at a huge commercial disadvantage as assets such as flares have to be shut off and inspected via traditional methods such as scaffolding, rope access or by being lowered to the ground. These options are hugely expensive and costs can run into millions of dollars a day in lost production.
An inspection technique using flying robots is now becoming established at industrial processing sites both on- and offshore to remove these problems for operators and owners.
The inspection of live assets by Remotely Operated Aerial Vehicles (ROAVs) was developed by UK engineering inspection company Cyberhawk as a safer and easier methodology to inspect tall or difficult to access structures. It significantly de-risks projects in ways that traditional inspection methods involving scaffolding and rope access simply cannot.
These miniature flying vehicles use HD video, HD still and thermal cameras to provide detailed images for inspection purposes. For safety reasons, ROAV inspections are always operated by a two-man team consisting of highly qualified plant inspectors and an experienced pilot. The combination of cutting-edge technology, expert pilots and experienced engineers culminates in the production of highly detailed technical inspection reports and analysis of a structure in a cost-, time- and safety-efficient manner.
The Cyberhawk ROAV itself is small and lightweight and has been carefully adapted to ensure optimal performance in the harshest of on- and offshore environments. Being battery powered the ROAV is quiet in operation, and, importantly, eliminates the need to have liquid fuel on site.
The ROAV survey of Brent Delta saved Shell £4.6m
With eight independent rotors, the Cyberhawk ROAV can be positioned with great accuracy, and state-of-the-art GPS positioning technology means that the exact image can be accurately repeated if necessary. This is a vital element of asset monitoring as it means that the structure can be compared over time from the same position to show degradation, and repairs can be scheduled based on real engineering data. Often repairs can be deferred until a planned shutdown, which allows for a more strategic approach to maintenance: specialist parts can be manufactured, budgets prepared and timetables arranged based on the robust engineering data and analysis that are provided as part of the ROAV inspection.
The ROAV can be up in the air in a matter of minutes and results generated from the inspections can be available in hours – as opposed to many days using ‘traditional’ methods. In fact, sometimes reports (or even just the images) produced from traditional inspection methods at offshore locations can take weeks to be delivered as information is fed back to the onshore team to be compiled and then relayed back offshore.
Cost savings in offshore inspection
Working with asset integrity management company Stork Technical Services, and building on experience gained at numerous onshore inspections, Cyberhawk carried out a structural and coating inspection of an offshore drilling derrick for Shell UK Limited at their Brent Delta platform. This was the first ROAV inspection of a live offshore asset.
Stork wanted to look at the paintwork on the derrick as it neared decommissioning. Cyberhawk’s ROAV captured HD images and relayed them live allowing for a full assessment of the structure and coating condition of the operational drilling derrick. The inspection involved accessing areas that would have been particularly challenging and time-consuming for traditional rope or scaffold inspections. The inspection was delivered during live drilling operations and there was no requirement for a costly shutdown, which would have cost an estimated £80,000 - £100,000 per day.
A ROAV pilot on the platform helideck
The results from the visual inspection allowed Stork to challenge the workscope and reduce the quantity of the surface area to be treated by 42%. In addition, the results allowed the introduction of a wax oil preservative coating to treat the drill derrick, which delivered with a further saving of 1,725 man-hours. The wax oil coating workscope could be delivered in a 14-day period compared with six weeks for conventional paint treatments. This allowed the work to be carried out during a planned pause in drilling, rather than a lengthy shutdown, giving an overall project saving of £4.6million which would not have been achieved without the data gathered and engineering expertise supplied by the ROAV inspection.
Developing the range of ROAV inspection on the Brent Delta platform
Initial deployment on the Brent Delta led to subsequent work on the platform when Cyberhawk carried out a condition assessment of the platform’s underdeck. There was a subsea element to the work, as Cyberhawk was tasked with looking at the risk of dropped objects to divers. Rope access and scaffolding would once again have been time-consuming, involving many more hours and exposing people to real risks of working at height and over the edge of the platform.
As always, the Cyberhawk survey was carried out by a two-man team and took 3 - 4 days to complete. An inspection using traditional scaffolding and rope access would have taken around 4 weeks to complete using a three-man team.
The project posed some real challenges as it was the first time that an inspection had been carried out in a completely GPS-denied environment. All flying had to be done manually, a feat undertaken by Cyberhawk’s full-time pilots with many thousands of hours flying time. Again, experience gained in other situations and the skill levels of operators were decisive in achieving the outcomes.
Underside inspection took a fraction of the normal time
An expanding range of applications
The cost, time and safety improvements over traditional methods of inspection mean that the ROAV is already becoming established as the preferred option for industrial surveys and inspections in the UK and globally. A proven offshore ROAV inspection pedigree has led to Cyberhawk being brought in to carry out work on live flare tips and other offshore structure from the North to the Irish Sea, and from the Norwegian continental shelf to the South China Sea. It is a prime example of how North Sea technology can be adapted and applied to conditions all over the world.
The influence of ROAV technology may very well be even more wide-ranging than originally envisaged. It could well be that a point is reached in the future that facilities are actually designed with the intention of operating and maintaining them using remote vehicles.