Repsol and Spain’s Indra have teamed up to deliver a fully automated early spill detection system, said to be the first of its kind. Russell McCulley finds out how it works.
Marine environmental surveillance requires a high degree of skills — the ability to correctly interpret data from sensors, to spot the tell-tale signs of a slick, and the ability to make the right calls for a quick response, to name a few.
However well honed those skills may be, human error is still a risk. And the equipment used to detect spills, such as infrared cameras and radar, may not function well in certain weather conditions, or may identify slicks that turn out to be false alarms.
The new system developed by Repsol and Indra, dubbed Hydrocarbon Early Automatic Detection System (HEADS), combines infrared camera technology and radar, underpinned by sophisticated algorithms, to create an automated environmental surveillance network that its developers say substantially reduces the risk of human error and provides more reliable information.
HEADS uses infrared images and radar to provide the bulk of detection data. Neither technique is new, but the way the system integrates them is novel, says Antonio Perez, project manager at Repsol Technology Centre.
“By integrating the sensors, we created a system that is able to determine if a spill is real with a high degree of truth,” he says.
Data from both sources is processed with automation software to allow continuous surveillance. The system includes a console located in a control room where routine operations are monitored. If a spill is detected, HEADS automatically activates an alarm and collects all relevant data, registering and analysing the related parameters.
Data driven
The integrated system provides a much more accurate reading than the instruments can manage individually, Perez says. “One of the issues with sensors is the false positive. You want a sensor to be reliable. What we did is a really robust and reliable system that combines two different sensors with algorithms. That’s the heart of the system.”
Industry environmental policies tend to focus on spill prevention — asset integrity and material handling practices, for example — and spill response, or protocols to follow in the case of an accidental discharge, he says.
“What we did was try to aim this system at the gap between prevention and response. The system is not meant for tracking spills after they have happened,” Perez says.
“It is really meant for monitoring your asset very closely, day-by-day, 24/7, so that you can notice every small incident in order to protect the asset and the environment.
“The aim at this very precise gap is what makes it different, and very useful.”
The sensors complement each other well — radar picks up very minor variations in the roughness of the water surface that can indicate the presence of hydrocarbons, while infrared detects differences in temperature between water and oil. The technologies have their limits — infrared’s thermal “vision” is impaired when the water surface temperature and the air above it are the same, and radar is ineffective if there is no wind to generate the backscattering effect that reflects waves and signals back to the source.
“The two of them respond to two very different physical phenomena, so by combining them you have wider coverage,” Perez explains. The combination also reduces the rate of false alarms.
“The hard part of the programme was to create a really robust algorithm to differentiate and discard what could be false positives.”
A team of more than 20 scientists and researchers from both Repsol and Indra began working on the HEADS programme in 2009, says Repsol’s Jose Solano, manager of the company’s Valorisation of Technology unit.
“We were looking for technology to detect spills and prevent incidents,” he says.
“We discovered that there was no technology to give this sort of early detection.”
Most existing systems relied on an expert to monitor sensor signals and make judgment calls.
“There just wasn’t the kind of technology we wanted to monitor our assets,” he says.
Researchers examined more than 30 different types of sensors before settling on the infrared and radar combination. Algorithms were developed under laboratory conditions, followed by tests at Repsol facilities in the port of Tarragona, Spain.
The rollout
The HEADS pilot, deployed early in 2014, comprises a surveillance system at a pier in Tarragona and another installed on the Casablanca production platform 40 kilometres off the coast. Both have demonstrated “very good performance”, Perez says, with some necessary fine-tuning. The companies are now offering the system commercially, with further coastal installations planned in Spain and Peru. Repsol is looking at extending HEADS to its offshore assets, which grew in number with last year’s $8.3 billion acquisition of Talisman Energy.
Offshore, the typical set-up consists of two infrared cameras and two radar units.
The radar equipment has a range of three to four nautical miles, and the infrared cameras cover an area ranging from 200 metres up to five kilometres from the platform, depending on the desired resolution.
The kit is small, easily installed on the corners of a rig, and can communicate via fibre optics or wirelessly, Perez says. Historic metocean data helps determine the exact set-up, and a few weeks of fine-tuning optimises the system’s performance.
“At each location, when we set up the equipment, we need to make a fine tune of the metocean conditions and possible interference,” Perez says. When properly tuned, HEADS produces “very few false positives”.
“From the beginning of the project, one thing was important,” he continues. “We didn’t want a system with an expert in a control room watching the radar and the infrared camera. We wanted to be integrated in the normal control room operation.
“With this system, all the hard work is done by the algorithm, and it can be integrated to the control room.”
The system incorporates automatic identification system technology, which identifies any nearby vessels and helps determine if a spill is coming from one of them. HEADS also records data for auditing and traceability, much like an aircraft’s “black box”, and boasts a response time of less than two minutes.
The technology is not applicable for large spills, but for slicks involving relatively small amounts of fluid. That’s the point, says Perez. “We believe that before there is a big event, there are many small events, maybe two litres, five litres. And this system helps protect the asset, because it’s telling you how the day-to-day operations are working — if your pipelines are getting old, if your seals are well connected or not. It’s meant as much for protection as for response.”
石油圈
