In May 2020 The American Petroleum Institute (API) and the Association of Oil Pipelines (AOPL) released their 2019 Pipeline Safety Excellence Performance Report. Encouragingly the report highlights a number of positive safety trends — most notably that total liquid incidents impacting people or the environment have decreased by 36% in the last five years, while total pipeline incidents are down 17%.
Over the same timeframe, liquid pipeline mileage has increased nearly 10%, including a 20% increase in crude oil pipelines, while total barrels delivered increased by 35% from 2014.
Clearly it’s great to see the industry’s strong commitment to safety and reliability, and that positive progress is being made in terms of reducing the number of incidents. But as AOPL President and CEO Andy Black acknowledges, more work is needed to decrease these figures further. The ultimate goal has to be zero incidents.
Accompanying the API and AOPL report is a strategic plan that describes industry-wide safety improvement efforts over the next three years designed to promote organisational excellence, harness technology and innovation, increase stakeholder awareness and engagement, and improve emergency response preparedness.
Although Distributed Acousting Sensing (DAS) is mentioned — briefly on page 24 of the report as part of a recap of the API and AOPL’s 2017-2109 strategic plan — it’s disappointingly and suprisingly overlooked.
In my view, if authorities and pipeline owners are serious about that zero incidents goal, then DAS has to be part of the picture and rolled out on as much pipeline infrastructure as possible. No one technology can provide a panacea to the challenge but DAS is a proven technology for increasing the efficacy of leak detection systems and should form an integral part of any pipeline management system.
DAS for leak detection
A DAS interrogator converts a standard communications single mode fibre into thousands of extremely sensitive acoustic and vibration sensors.
The Distributed Acoustic Sensor connected to one end of the fibre uses a laser to send thousands of short pulses of light along the fibre every second. A small proportion of the light travelling in a fibre is reflected back by the process known as Rayleigh Backscatter.
Vibrations from the surrounding environment, will disturb the light in the fibre and will therefore be observed by the DAS interrogator. As the data is processed in real time, advanced algorithms are able to recognise the unique signatures of each type of event and report those events that are of concern to the alarm server. Information about the precise location of the threat and information about what event has taken place is sent to the operator in real-time. This gives the asset owner the opportunity to make a timely and proportionate response.
The fibre is the sensor
The simplest way to think about this technology is to imagine a series of thousands of microphones distributed along the length of your asset, every microphone is monitored, and we can track multiple events simultaneously.
The frequency with which we can pulse the laser is determined by the length of the fibre, as we can only have one pulse of light in the fibre at a time. This in turn, determines the acoustic bandwidth of our sensor.
Fotech’s LivePIPE DAS leak detection solution has been proven in the field and been regurously tested and proven in 359 lababoratory tests using varying pressures, cable designs and offset distances. In every scenario LivePIPE detected the leak with zero false alarms.
While some leak detection systems record a set of baseline operating conditions and then monitor for unexpected changes, if a pipeline is closed for maintenance and then reopened, the characteristics can change, and the relevant changes may not trigger an alarm. In contrast, Fotech’s DAS technology detects the vibrations and strains in the soil, caused by fluid actually escaping and is therefore not affected by changes in the pipeline operating state.
Enhancing operator maintenance
By providing continuous monitoring of the entire pipeline DAS can provide a vital layer of additional intelligence – pulling information gleaned from other monitoring and maintenance sensors into a big picture view of what is happening on the pipeline at any given moment.
These capabilities can provide significant enhancements to operators’ safety and maintenance efforts. Maintenance of ageing pipelines is in many ways more difficult and less ‘sexy’ than preventing criminal attacks, but it is no less important.
Operators need monitoring solutions that offer genuine coverage and insight when it comes to maintenance issues. As such, DAS should be an integral part of those solutions, acting as the ‘glue’ that holds disparate maintenance sensors together to provide complete maintenance monitoring across the whole pipeline.
Setting new standards
Fotech’s DAS technology challenges the standards for leak detection. Many of the State Companies specify a requirement to detect a leak equivalent to 1% of the flowrate of the pipeline. In a pipeline transporting 100,000 barrels of oil per day that 1% equates to 1,000 barrels. If it takes just 6 hours to identify a leak, 250 barrels will have escaped. In contrast, our DAS tests — based on a leak of 20 litres per minute —detected and raised the alarm in just 90 seconds, by which time only 30 litres had escaped. It’s an improvement by a significant order of magnitude.
That’s why we believe DAS can have such a key role to play in helping the API and AOPL get closer to its holy grail of zero incidents.
For a deeper dive into the role DAS can play in supporting pipeline leak detection I’d strongly recommend our whitepaper.