Geolocate buried pipelines using magnetic field measurement

Since 2016, start-up Skipper NDT has been developing technology to map buried pipelines carrying oil, gas and water, using a drone equipped with magnetic signal sensors. The process has now entered a commercial stage. Interview with Maher Kassir, the co-founder of the company.

90% of the world’s oil, gas and water produced is carried through an extensive network of underground pipelines. These pipelines are very effective in carrying these materials, but still require regular monitoring. After working for thirty years in the field of entrenched pipeline protection systems, Maher Kassir decided to create a start-up with his son Luigi to develop new geolocation technology for these infrastructures. After more than five years of research and development, with the help specifically of CNRS and Cachan University, the company has entered a stage of commercialization of its process. Meeting with the co-founder of Skipper NDT.

Engineering Techniques: Why is it important to geolocate pipelines?

Maher Kassir, co-founder of Skipper NDT. Credits: Skipper NDT

Maher Kassir: Any incident on these structures can have a noticeable impact on man, environment and material. Over time, they can be subject to landslides, landslides, but also damage caused by surface works. For example in Belgium in 2004, when an excavator hit a pipe, which caused, two weeks later, an explosion that killed 24 people. Regulations are increasingly demanding and what was acceptable ten years ago is no longer acceptable today. In France, a law called the DT-DICT or anti-damage law requires underground network operators to geolocate them with an accuracy of at least 40 cm. In the United States, in extreme weather such as floods, installations must be inspected within 72 hours to verify that no rupture has occurred. There are also economic reasons for better monitoring. Fifteen years ago, in the Gulf of Mexico, an oil spill cost BP 50 billion euros.

Even water pipes have been subject to increased surveillance in recent years. In their contracts, water managers now impose clauses on pipeline operators asking them to fix leaks, so that they no longer have to pay the cost.

The centimetric geolocation of these buried structures makes it possible to avoid the large majority of incidents due to surface works.

How does your technology work?

Some earth metals, such as iron or cast iron, generate magnetic signals. Thanks to our sensors, we record these signals using a technology, but it’s not really new. Our added value is to develop a family of algorithms capable of converting these magnetic signals into 3D geographical positioning and thus succeed in mapping these pipes to the ground with an accuracy of 20 cm. on average. At this point our innovation was based, and became the subject of a patent.

What types of algorithms have you developed?

They can be schematized in two families. First of all, the cleaning algorithms that make it possible to overcome all the defects associated with a magnetic measurement by drone. They convert raw data, subject to sensor deficiencies and interference, into a useful signal with the lowest noise and lowest bias possible. These are, for example, attitude correction algorithms based on inertial units, calibration/compensation algorithms for our magnetic sensors, as well as multispectral filtering and various types of positioning correction. satellite.

Then, we use proprietary pipeline detection and georeferencing algorithms. These apply to cleaned and paid data allowing the creation of a magnetic map of the inspection area. Through the inversion method, based on a magnetic response model of the pipes we developed, the algorithms are able to locate the source of the magnetic signal measured on the map of the inspection area in an accurate, stable and repetitive manner.

Map of the magnetic field of two buried pipelines. Credits: Skipper NDT
Layout of pipelines in the background of the map. Credits: Skipper NDT

What are the advantages of your process compared to existing ones?

Conventional systems such as electromagnetic measuring rods and ground penetrating radar GPR (Ground penetrating radar) require the presence of an operator who moves the ground and examines the ground using a device. Therefore, it is necessary to deploy someone on the site, which is time consuming, costly and presents the risk of being inaccurate in the face of human error. GPR radars also have the disadvantage of not working under certain conditions, especially on clay soils or water -saturated soils. For our part, we installed our equipment along with its sensors on a drone capable of flying without human intervention, thanks to a pre-defined flight plan. Therefore, the data is automatically collected by the drone, then automatically interpreted by our algorithms. In addition, we are the only technology capable of geolocating, in a rural environment, the buried cast iron networks used in water transportation.

The drone is equipped with sensors for measuring the magnetic field. Credits: Skipper NDT

What are the results obtained on the geolocation of the pipelines?

We first tested our system on a test bench at Cetim (Technical Center for Mechanical Industries), developed in partnership with TotalEnergies. Then, we conducted the first full-scale trial of GRTgaz last year. This was successful, and we continued our tests with the goal of geolocating pipelines at several sites with different configurations in terms of pipe diameter, depth and terrain type. As a result, we managed to find them at 89%, according to the class A standard. This is the highest accuracy class of the standard established by the French regulations and imposes mapping of networks with an accuracy of less than 40 cm. The remaining 11% can be explained by flight difficulties in some areas, primarily due to the availability of roads and the fact that we do not have flight permits. Faced with this restriction, we developed a ground machine that moves on the roads.

We also performed several tests on different pipe configurations using Véolia and got results.

The main limitation of our technology is that more than 15 meters deep, the geolocation of the pipes is not possible, because the magnetic signal is lost. But pipelines are very rarely buried at such depths, because they are expensive.

At what stage is your project?

We are currently in the commercial phase. In France, we signed contracts with GRTgaz and Véolia as well as with TotalEnergies for an intervention in Nigeria. In the United States, we work with two major operators: Enbridge and Kinder Morgan. In Asia, we also signed and executed a contract with the oil company Petronas in Malaysia. These contracts cover a variety of services, such as the geolocation of onshore pipelines, sub-river crossings or the detection of mechanical deformations.

At the same time, we are continuing our research work to improve the performance of our system, specifically with the goal of reducing the weight of our drone equipment. It currently weighs 4.2 kg and we want to reduce it by half. By reducing weight, the drone will have more autonomy and our technology will be easier to deploy, especially in terms of transportation.

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