Last month Reuters announced that French energy group Total was auditing the pipeline supplying its Grandpuits refinery near Paris following a series of leaks. A leak last year, following a previous spillage in 2014, halted output at the refinery for several months.
The PLIF pipeline in question brings crude oil from Le Havre port to supply the Grandpuits refinery, which has a capacity of 102,000 barrels per day. Total’s audit is exploring the cost of replacing the 260km pipeline — a figure French trade union the CGT estimates will likely be in the region of one million euros per kilometre.
It is also reported that Total is facing an 80 million euros bill to conduct major maintenance, which is due by early 2021 (under its seven-year maintenance cycle).
With an update on Total’s pipeline audit expected sometime in the autumn this seems like a perfect time to discuss the role Distributed Acoustic Sensing (DAS) can play in the maintenance of ageing pipelines — both in terms of identifying leaks faster than traditional leak detection systems and minimising soil contamination.
Real-time visibility of pipeline integrity
Total’s 52-year old Grandpuits pipeline, like the majority of the pipeline infrastructure in use globally today, was built between the 1950s and the 1970s. This ageing infrastructure represents a serious challenge for operators. Much of this network was simply not built to the size and strength required for today’s product volumes, which are larger and are transported under much higher pressure.
Clearly, for these ageing pipelines proactive maintenance operations are absolutely vital. To be effective, maintenance operations rely on digital monitoring solutions that provide genuine coverage and insight.
There is a plethora of maintenance technologies available. However, too often we see these technologies being deployed as standalone solutions which limits their ability to provide comprehensive monitoring.
On ageing pipelines, incidents could happen anytime, anywhere on the pipeline. As a result, operators need systems that enable them to maintain maximum vigilance across the whole pipeline to minimise the impact of any incidents. Unfortunately, standalone maintenance systems are unable to achieve this level of monitoring.
For example, commonly used mass balance sensors – which can detect changes in the mass of product entering and exiting pipelines – may only be able to pinpoint an incident to a section of pipeline several kilometres in length. This makes it impractical as an information source when rapid responses are required.
Instead, maintenance operations need to more closely resemble the integrated SCADA systems that are in place to deal with third party intrusion-type incidents. And, much like in security scenarios, DAS-based monitoring solutions have a big part to play in beefing up maintenance efforts.
By providing continuous monitoring of the entire pipeline DAS can provide a vital layer of additional intelligence – pulling information gleaned from other maintenance sensors into a big picture view of what is happening on the pipeline at any given moment. For example, DAS can validate or add to signals from pressure sensors that can help identify potential corrosion incidents. DAS can also assist with other crucial maintenance operations, such as PIG tracking.
These capabilities can provide significant enhancements to operators’ maintenance efforts and help to more cost effectively extend the safe and useful life of the pipeline.
DAS for leak detection
In the worst-case scenario – where a leak occurs – DAS again can provide help by detecting the vibrations and strains, caused by escaping product. The role DAS can play in supporting pipeline leak detection is a subject we’ve discussed many times and is covered in-depth in this whitepaper.
Proven in the laboratory and in the field, Fotech’s LivePIPE DAS leak detection solution has been tested against varying pressures, cable designs and offset distances, and in every scenario, consistently detected leaks with zero false alarms.
Some leak detection systems record a set of baseline operating conditions and then monitor for unexpected changes, but if a pipeline is closed for maintenance and then reopened, the characteristics can change, so consequently, 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.
Typically, the timescales for detecting pipeline leaks can extend into hours and even days. In contrast, with DAS can achieve an improvement by a significant order of magnitude, with leaks being detected and an alarm raised in a matter of seconds.
Extending the safe and useful life of pipeline networks
Maintenance of ageing pipelines is in many ways more difficult and less ‘exciting’ than preventing criminal attacks, but it is nevertheless, just as 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.
As in the case of Total’s Grandpuits pipeline, the economic cost of replacing a pipeline is significant — as is the logistical challenge involved. Enhancing proactive maintenance operations that help to extend the safe and useful life of the pipeline network by many years must be a more cost effective and attractive option for operators. By using DAS, Total could achieve the much-needed step-change in their maintenance operations.
For a deeper dive into the role DAS can play in protecting pipelines, we’d strongly recommend this video.