The offshore oil & gas industry has long relied on sensors and sporadic ROV footage to find out what's going on subsea. Now a new tool designed for permanent deployment at well sites is about to change all that, according to Weatherford's Ole Tom Furu. He tells Jennifer Pallanich how.
Borne of the need to reduce the number of false leak detection alarms attributed to subsea sensors, the SeaHawk subsea video surveillance system can record images at subsea wellheads.
By perching a SeaHawk camera on a tripod or a guidepost stand, says Ole Tom Furu, business development manager for subsea technology for Weatherford, ‘you can be alerted to a potential problem and then you can see if it's a leak or not' without having to deploy an ROV every time the alarm sounds.
‘We've had enough accidents worldwide,' Furu says. ‘I think this type of equipment needs to be installed worldwide, everywhere.'
Such a permanently deployed subsea video system – named after the bird of prey with ‘very good eyes' – can be used not just for environmental monitoring for leaks he says, but for condition monitoring, such as vibration analysis, and safety monitoring, such as diver or ROV activity.
Cost effective
The benefits, Furu points out, come from reduced production downtime associated with fewer false alarms and a more secure gas lift operation. Using video surveillance, he adds, is cost effective compared to ROV inspections, and the systems can be retrofitted on existing infrastructure by adding new instrumentation. Finally, he notes, it can be used around the clock without constant human monitoring.
Norwegian regulations require two barriers be in place for offshore gas lift operations. Furu sees the titanium-encased SeaHawk unit as something that can be used alongside those barriers.
‘This can be the third, not exactly a barrier, but another line of defense against catastrophe,' he says.
In 2005, a company called Sicom was developing the subsea video camera in Norway. After Weatherford's purchase of Sicom, the camera was ultimately installed in the Åsgard field in 280m of water in the North Sea for Statoil in 2007 to monitor possible leakage in a subsea valve, with Furu serving as project manager. Two more of the SeaHawk units were installed in 2009 at Statoil's Kristin field in 370m of water and Statoil's Heidrun field in 350m of water. The Kristin camera was installed to observe possible leakage of chemical injection activities while at Heidrun the camera was to observe possible leakage on a treecap and to monitor gas lift activities for leaks.
A further pair were delivered to the Heidrun field in the North Sea in 2011 to observe possible leakage on the template and to look for leaks during gas lift operations. Both were installed about 6.2km away from the Heidrun platform with a bandwidth of about 10MB/second to both.
A new camera will be delivered to Statoil Snorre B for structural monitoring in the North Sea in January 2012.
Pan and tilt
A more robust version of the SeaHawk system is now available, and is the first pan & tilt unit available, says Furu. An operator in the control room can operate the pan & tilt actions of the camera to view and video what's happening at the wellhead up to 120km away.
Camera and light are positioned on the top of the unit, with the cables attached in back. ‘We need to have cables with high reliability,' he says.
The latest version also boasts a longer design life – 20 years – and higher levels of reliability. That reliability, Furu says, comes in the form of double redundancy on many features and durable components.
Standard components are ‘not good enough for subsea installation,' Furu says. ‘For subsea installation, the design lifetime of the unit needs to be as long as possible.' To increase the SeaHawk lifetime the pan & tilt unit is built inside the canister dome. All cables between the camera controller and the lights, pan & tilt and the camera are protected inside the camera canister, he notes.
To be of use, video cameras must transmit data efficiently. ‘Video cameras need a lot of communication capacity,' as Furu terms it. As such, the SeaHawk system can be connected up to 50km away (via DSL) or up to 120km away (via fiber optics) from the modem topside.
Power requirement
A secondary determination is power. ‘Power in the oilfield is a problem today. You don't have enough power.' Furu says Weatherford has been focused on lowering the power consumption of the design. As designed, the camera, which features eight 800 lumen LED lights and can be deployed in water depths to 3000m, will have a maximum power consumption when using all eight lights of 80W.
Minimum power consumption when using one LED light is 30W. Grouping up to four cameras into one hub and running the lights on all the cameras will lead to a maximum power consumption of less than 400W, plus the operator can control which cameras operate at designated times.
Additionally, the operator can use any number of lights while recording. In a one-camera set up, the SeaHawk Camera and Light module connects via a DSL and power jumper to the topsides, where it connects to the ethernet, which transmit data as needed to on-site video monitors, the SeaHawk server and a control booth.
With multiple cameras, each of the cameras connects to a hub, and the hub connects via the jumper to the topsides. Multiple hubs can be daisy-chained on the seabed. OE
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