Tag: distributed sensing systems

Fiber Bragg Gratings for Civil and Geotechnical Engineering

Specialists have already found a series of applications where fiber Bragg gratings have shown to be profitable. FBG sensors have become a reliable distributed sensing solution for structural health monitoring. In addition to other applications, such as in the biomedical field, they are also used in civil engineering and geotechnical engineering.

All these areas have one thing in common – the environmental conditions. In such environments, it’s difficult to prevent the degradation processes such as aging and chemical effects. These factors should also be taken into account when implementing the traditional monitoring systems or equipment. In most cases, they have a short service life and require frequent replacement.

Alternatively, fiber optic sensors deliver modern fiber optic solutions that are able to work in extreme environments. FBGs for Civil and Geotechnical Engineering

Fiber Bragg Grating Sensors Common Characteristics

Since their first implementation, FBG sensors have been broadly deployed especially for distributed sensing of temperature, strain, and other characteristics that are particularly valuable in geotechnical and civil engineering. Fiber optic sensors have become world renowned for the features they offer. High sensitivity, immunity to electromagnetic interference are the most important parameters that are in demand.

Like traditional sensors, FBG interrogators face similar challenges. For example, they are usually required in extremely accurate equipment. That’s why there’s a high demand for maximum precision and high spectral resolution, down to picometer level. Fiber optic devices are also increasingly being used to deploy in rugged environments.

Fiber Bragg gratings are compact and can provide stable operation and durability in outdoor environments. For example, they are typically exposed to moisture influences, chemical reactions, temperature variations, etc. Distributed sensing systems should meet all the necessary requirements to ensure safety and proper operation of the entire system and to avoid the consequences of the interaction of the sensing element with the environment.

To ensure that, fiber optic systems should have robust materials and construction. In addition to complete, reliable fiber optic systems, fiber optic cables play a crucial role in creating the long-term FBG structural health monitoring systems. All fiber optic sensors should be able to withstand a certain level of thermal and mechanical loads at all times. The only way to provide customers with the best fiber optic solution is through testing of FBG sensors and application methods.

FBG Inscription Methods

Depending on the application and environmental conditions in which the FBGs are to be used, specialists can design FBG sensors for individual customer parameters.

A fiber Bragg grating is a fiber optic microstructure in which the index of refraction within the optical core changes along its length. The producing process of FBGs is usually called “writing”. Nowadays, there are three FBGs inscription methods:

The interferometric method is based on exposing a light sensitive area of the fiber to an interferometric fringe pattern to get the full grating. The pattern is achieved by illuminating an appropriate mask. In this case, the phase mask period defines the FBG period.
Continuous core-scanning method. Here, the FBG writing is provided by the motion of the translational frame where the fiber is fixed. In this technique, the period of the FBG is defined by the modulation frequency and the translation speed of the fiber.
And the last is the direct point-to-point method based on the absorption of a laser pulse. Each grating element is generated by controlling the laser parameters and moving the fiber. In this technique, the FBG period is determined by the fiber translation speed and the laser pulse repetition rate.

Applications of FBG Sensors

Fiber Bragg grating sensors are used in various fields where it is required to monitor structural health. In engineering, they are used to monitor the integrity of the entire structure and observe any deformation of its components. Such monitoring leads to the reduction of the risks and safety requirements. Fiber optic sensors are particularly useful for reinforced concrete structures because they can provide online data on the risk of corrosion.

When we talk about geotechnical and civil engineering, FBGs have also found their place for implementation.

Here are some examples of how fiber optic technology gets used:

Concrete structure monitoring;
Lateral deformation monitoring of embankment soft soil;
Pressure monitoring of tunnel’s rock and soil;
Structural health monitoring of bridges, dams, etc.

Nowadays, FBG sensors are also used to monitor landslides and slope failures and have shown good results. Distributed sensing systems have been applied to examine the landslide stability and deformation of landslides. Nevertheless, installing monitoring systems in complex environments and dealing with uncontrollable boundary conditions require careful consideration of potential issues.

Monitoring engineering and geotechnical structures with distributed sensing systems can improve profitability. Structural health monitoring methods are often preferred due to their ability to:

operate in chemically aggressive environments;
their feasibility in hard-to-reach areas of structures;
use fiber optic solutions which reduce equipment costs by utilizing a single fiber optic cable.

Overall, fiber Bragg gratings find extensive use in geotechnical and civil engineering applications. And, as with any technology, the successful implementation of fiber optic technology requires specialized experience and professionalism in designing and implementing the entire fiber optic system. Most of all, when there is a need for long-term measurements.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, FBG strain sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in structural health monitoring systems and want to learn more, please contact us at info@optromix.com

Fiber Optic Sensors for Li-ion Battery Cells

Fiber optic sensors have found a number of applications where there is a strong need for temperature monitoring. The use of Li-ion batteries is no exception, and specialists have learned to use fiber optic sensors for them as well.

Temperature monitoring of Li-ion batteries is an essential aspect of their operation in the field, and the problems of temperature monitoring can be solved with the help of fiber optic sensors.

FBG Sensors for Li-ion Battery Cells

What are lithium-ion batteries?

Li-ion, or lithium-ion battery is the most common rechargeable battery that uses the reversible reduction of lithium ions to store energy. Each module consists of one or more individual cells, which are consistently connected to follow the necessary rates of voltage, energy demand and power.

Typical Li-Ion BMS includes a few thermistors to monitor on selected cells surface temperature. This means that there is a possibility that cells may heat up invisibly.

Due to the wide deployment and large number of cells in each module, there is a need for modern technologies that can monitor cell operation and prevent future catastrophic failures.

The most common problem is the significant increase in temperature and strain in the cells. The effect of high temperatures and heat production from the cell can induce a series of degradation processes, resulting in reduced capacity and performance degradation. This problem is perfectly monitored with modern distributed temperature sensing modules.

The Temperature Effect on Li-ion Batteries

Distributed temperature sensing is used because the operation of Li-ion batteries can be affected by the influence of low and high temperatures. That’s why it is necessary to maintain comfortable temperatures during operation, storage and charging.

Temperature deviations from the ideal values may occur. However, they should still be within the established operating range. In addition, the critical temperature points shouldn’t be reached. Because of the test fields, continuous use in marginal conditions leads to accelerated wear of the battery and deterioration of its technical parameters.

Cold and overheating are both undesirable and harmful for lithium-ion batteries. In cold temperatures, they can experience voltage drops, deterioration of current output and rapid discharge. However, these symptoms disappear as the temperature rises. Overheating is more dangerous to batteries. It shortens their life and reduces their performance characteristics. There is also a risk of fire in the power source.

Maintaining optimal temperature regimes during battery operation extends battery life and ensures safe use. That’s why monitoring with distributed temperature sensing is an essential element for the correct use of Li-ion batteries and the prevention of emergency situations.

Fiber Optic Sensors for Li-ion Batteries

For Li-ion batteries, fiber Bragg grating sensors have been used to obtain data on distributed temperature and strain on the battery surface in various operating conditions. Specialists use the data obtained from distributed sensing systems in real time to detect abnormal conditions and prevent battery failure.

According to the field experiments, FBG sensors have been proven to sense the temperature either in the cells or between the cells when they are placed between battery cells. As a result, fiber Bragg grating sensors are able to provide the thermal information of each cell in a battery.

Lithium-ion Battery Applications

The lithium-ion batteries are commonly used to provide uninterrupted power in data centers, factories, air and water vehicles, and other facilities. Compared with the other types of batteries, they are smaller and have a longer service life. However, there is one drawback that should be considered in its implementation. A battery contains an electrolyte that decomposes into flammable components. Today, specialists have greatly reduced the potential for explosion to the maximum, but there are still risks. That’s why fiber optic sensors are very useful for monitoring.

The commercial battery industry also includes primary batteries as one of the major segments. However, it has its peculiarities, including non-recyclable materials and hazardous components in the batteries, which also cause ecological problems.

All in all, the knowledge of the temperature distribution in a cell or between several cells is fundamental for the safety of the battery. Fiber optic sensors have proven to be suitable for both temperature and strain gradient monitoring.

distributed sensing systems distributed temperature sensing fiber Bragg grating sensors fiber optic sensors

Distributed Sensing Systems for Leak Detection

The increasing role of the oil and gas industry has led to development of many related technologies including distributed sensing systems. Among other things, they have become a part of the leak detection technology that has proved to be one of the most powerful.

For development of the most cost-effective detection technology there should be a balance between three elements: well-trained staff, properly configured distributed monitoring systems and proper operations’ arrangement. By observing these conditions, the effective operation is achieved.

With distributed monitoring systems, the pipeline management leads to the fast detection of any accidents, thus, reducing the extent of damage, as well as unforeseen expenses. Distributed Sensing Systems for Leak Detection

The Most Common Classification of Distributed Sensing Systems

Distributed sensing is a continuous monitoring technique which operates across the whole fiber optic cable in real time.

In contrast with the conventional sensors that were previously applied, distributed sensing systems use the whole optical fiber instead of the separate sensors that measure parameters in certain points. For this reason, fiber optic systems are easier to install even in heavy ambient conditions. With fiber optic cable, specialists have no need in defining particular locations where sensors should be placed. This fact makes the monitoring process more cost-effective.

The distributed sensing systems are different due to the data they require. So, there are distributed acoustic sensing (DAS) or distributed temperature sensing (DTS).

Distributed temperature sensing (DTS) uses a fiber optic cable that serves as linear temperature sensors. Eventually, specialists get the full temperature profile for the required period.
Operation principle of the distributed acoustic sensing (DAS) is similar to the DTS system. It applies a fiber optic cable as well, that provides the data. However, instead of registering temperature changes, they are relying on the acoustic and vibration changes in fibers.

Applications of the Leak Detection Systems

Leak detection fiber optic systems are installed to get the information about any appearing changes in parameters and leak possibilities. The distributed monitoring systems are able to find leaks almost instantly.

Here are a few examples where fiber optic sensing systems have found their applications:

One of the last well-known developments connected to fiber optic sensors is the monitoring of offshore Arctic fields. Pipelines are constructed for safe transportation of oil and gas avoiding any leaks. However, there are high risks of their deformation because of the severe environmental conditions like the effects of ice gouging, permafrost thaw settlement, or physical damage. The absence of fiber optic monitoring systems may result in severe environmental, and economic impacts.
Distributed sensing systems can be also applied for liquid sodium leaks monitoring. Fiber optic sensors can be implemented into various nuclear power plants and other facilities. Electromagnetic immunity, ability to resist high temperatures and operating in radioactive environments make fiber Bragg grating sensors a powerful instrument in monitoring.
Distributed monitoring systems are also used at wastewater treatment plants. The leak can lead to dangerous consequences such as spillage of contaminated fluids and therefore environmental damage.

Main Purposes of the Fiber Optic Technology Applications in Leak Detection

Fiber optic sensing systems bring many benefits while using. As a result, they have become useful instruments and can be applied for different purposes. Firstly, distributed monitoring systems are usually used for monitoring any changes that take place over long distances of the pipelines. Fiber optic sensors can monitor flow rates, temperature, pressure, ground strain, etc. All measured physical parameters are sent to the center where all the data is displayed with the help of the software.

Due to the received data from fiber optic monitoring systems, specialists are able to watch any changes or conduct the necessary calculations. In case of any changes, the operator or security personnel gets a signal that there are changes and sees their accurate site. So specialists can quickly respond to any changes and prevent any further possible damage.

The other purpose of distributed sensing monitoring is leak detection. Fiber optic monitoring systems can be installed both on buried and unburied pipelines. They can detect the precise location of the leakage in a short time. Moreover, they can discover other accidents like ground disturbances, theft, manual and machine excavation, etc.

Fiber optic monitoring systems designed for the oil and gas industry can also help in optimizing the lifetime of the wells. They are used as integrity monitoring instruments of the storage tanks, process vessels and other equipment. Considering all the information, specialists can make a decision on the maintenance programs as a means of extending the service life.

Due to all these possible applications, distributed sensing systems have found their place in the gas and oil industry. Fiber optic sensing systems have proved to be cost-effective in measurements of main parameters in pipes in the conditions of severe environmental and industrial equipment.

distributed acoustic sensing distributed monitoring systems distributed sensing systems distributed temperature sensing fiber optic monitoring systems fiber optic sensors

Distributed Sensing for Seismic Monitoring Systems

We have already published a range of articles referring to different applications of fiber optic technology in various industries and fields. Geophysics has also applied distributed sensing as a powerful instrument for structural health monitoring, such in, the oil and gas industry, tunnel safety monitoring, etc.

Seismic monitoring has been no exception. Resistance to electromagnetic disturbance, cost-effectiveness and possibility of implementing into hard-to-reach regions or places that can be harmful for human health are undeniable advantages of distributed sensing systems. Distributed Sensing for Seismic Monitoring Systems

What is Distributed Sensing Technology?

Distributed sensing is a technology that provides continuous measurements in real-time. Compared to traditional sensors, placed at certain points, distributed sensing acts as a sensing element along its entire length because the whole fiber optic cable is applied.

Due to the exploitation of the entire fiber optic cable all over its length, this method is considered to be one of the most cost-effective tools that can be placed in severe conditions.

Operation Principle of the Distributed Sensing Systems

In simpler terms, DAS systems as a part of the distributed sensing technology consist of several components including fiber optic cable and an attached optoelectronic device – FBG interrogator. The interrogator sends short pulses of the pulsed laser light into fiber optic cable. Then the backscattered light moves back up the fiber to the FBG interrogation unit. Due to the time that the laser pulse takes, there can be found the relation backscatter event and a fiber distance.

The FBG interrogator is connected to a processing unit that processes and stores the received data. This unit gets the raw data and transfers it into the information that is displayed in the program.

The software provides the visualized analysis that includes the previous data as well. In case there are any differences, fiber optic system alarms specialists. For instance, the system can display the location of the fiber optic cable on the map and highlight locations where the rates have changed or exceeded acceptable limits.

What’s the Difference Between DAS and DTS Systems?

Traditionally, distributed sensing systems are divided into distributed temperature sensing and distributed acoustic sensing.

The main difference between DTS and DAS systems is the type of signals they get to provide analysis. DTS systems are sensitive to temperature changes, while DAS is sensitive to acoustic vibrations. Therefore, their operation principle is also different. Due to the fiber qualities, the performance of DTS systems is able to stay at the necessary high injected pump power level. At the same time, DAS systems don’t require such high pump power as DTS systems because of the Rayleigh scattering.

DAS Systems and Their Applications in Seismic Monitoring

If we are talking about seismic monitoring, distributed acoustic sensing is used. DAS systems measure any vibrations that can’t be detected by DTS technology.

The goal of all seismic monitoring systems is warning before any accident occurs. Their effectiveness depends on the accuracy of the obtained data, lifetime and length. That’s why there is a necessity in a continuous operating system that is capable of working in severe environments and over long distances.

DAS systems were implemented as seismic monitoring systems due to the above-mentioned advantages as well as low cost, no special maintenance, robustness, etc. Therefore, distributed acoustic systems have provided new capabilities for seismic monitoring.

Field Projects Where Sensing Systems Were Applied

If we are talking about sensing systems, in most cases fiber optic sensors were more effective in comparison with the conventional electronic ones. That provides unrivaled performance, especially in critical applications.

For example, two years ago the specialists started a range of experiments in the Arctic and the Arctic Ocean. This is the first case when DAS systems were installed in the Arctic. Scientists wanted to get the analysis of the seafloor seismic activities and other processes under Arctic sea ice with a distributed acoustic sensing system. Fiber optic cable catches the vibrations about all the changes of the ocean 24/7.

The other project with DAS systems has also allowed scientists to see them in other severe environmental conditions. Since they are installed mostly in the ground, specialists have monitored their performance in snow. The most concerning parameters for them were the snow depth and severe frosts.

Finally, in the conditions of decreasing temperatures the reduction in background noise and better signal-to-noise ratio was noticed. In fact, the lower temperatures, the better results distributed acoustic sensing has provided. Cold temperatures don’t make fiber optic performance difficult or interfere with accuracy of the received data. Moreover, fiber optic cable is able to transfer signals at snow depths of at least 0.65m.

Distributed sensing as a tool for seismic monitoring systems has proved to be effective in detection of any seismic shocks and flow changes. All in all, DAS provides capabilities for seismic monitoring of the near surface.

DAS systems distributed acoustic sensing distributed sensing distributed sensing systems DTS systems FBG interrogators fiber optic cable

Dual Lasers in DTS Systems for Oil and Gas Wells

DTS systems provide the oil and gas and other industries with the new cutting-edge fiber optic solutions such as a groundbreaking dual laser technology which offers the most robust and the simplest distributed temperature sensing systems accessible to the industry. This technology also includes the ability of the automatic correction for dynamic changes to the sensing fiber.

What is Distributed Temperature Sensing?

Distributed temperature sensing, also known as DTS, is a technology that measures the temperature along the whole fiber optic cable in a continuous fashion. The fiber optic line can be any required length up to 30 km. The system includes the recording instrumentation at one or both ends of the cable. It can work permanently or from time to time for each use, depending on the requirements. Dual Lasers in Distributed Sensing Systems

Most Common DTS Applications

Distributed sensing systems have established themselves as an effective part of fiber optic technology. High temperatures are related to the severe environmental conditions which make operational processes difficult. However, fiber optic sensors can operate in such conditions greatly, especially, if we compare them with the electrical-based temperature sensors. That’s why fiber optic systems have found many applications, such as fire detection, healthcare, railways, etc.

DTS systems are installed on the electric power lines to monitor temperature changes. The temperature may indicate the electrical overload or other deviations from the norm in time. DTS technology allows power companies to exploit the assets more effectively.

With the help of constant monitoring, it is easy to react immediately to the temperature rising. When this rising is above a predefined threshold, the alarm sets off. The early detection and warning lead to reduction of the damage that failures may cause.

DTS Applications in the Oil and Gas Industry

Fiber optic technology has been used in the oil and gas industry for over the last 25 years. Fiber optic systems were installed in various types of oil wells starting from land wells and ending with offshore wells. Fiber optic technology allows watching down hole casing deformation or changes in sand screen completions.

Thanks to its operational principles, distributed temperature sensing offers critical asset monitoring solutions that can be applied for oil and gas companies. DTS systems immediately provide the actual and accurate information about temperature with high resolution and high speed. Fiber optic cable provides specialists with the numerous measurement readings along the whole optical fiber. This feature helps companies in detecting leaks along the pipelines, whether along its length or anywhere on the cross-section. The faster the leaks are found, the less damage can be. It means considerable cost savings for companies. Moreover, DTS technology helps in identifying under-performing zones, optimizing gas lift operations, etc.

Distributed temperature sensing has been applied safely to follow up pressure or reactor vessels. Depending on the required set-ups, the temperature measurements can be held as frequently as every 30 seconds. Any changes in temperature may point out some problems that have occurred. So the increasing temperature of the vessel wall usually predicts the system or the process failure.

Dual Lasers in DTS Systems

Each year, specialists implement DTS systems more often to make the efficiency of production better. The integration of the dual lasers into such systems is a new technology, aiming at the life extension of optical fibers and solving the most appearing concerns. The most common issues that optical fibers face are fiber darkening or their damage.

The fiber darkening can misrepresent the statements and lead to the failure of the DTS system. It occurs where there are high pressure and high temperature environments that are usual for oil wells. The darkening happens unevenly and is progressive over time that makes the manual calibration techniques ineffective. Moreover, different connectors on the fiber can result in various degrees of optical loss. Two lasers operate at different wavelengths, so there is an automated adjusting system for any changes in optical loss in the fiber. They immediately react and correct these effects which allows the further use without re-installation of the whole system from the very beginning.

Such fiber optic systems help in cost-reducing by avoiding the re-deployment of the equipment. Despite the other systems, they don’t need the manual calibration techniques, but operate automatically all over the length. The manual calibration usually requires repeated recalibration efforts.

Newly developed DTS systems with dual lasers offer great advantages especially where there is no or limited access to the optical fiber. They help to extend the lifetime of the fiber and ease fiber optic systems’ deployment.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, fbg strain sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in structural health monitoring systems and want to learn more, please contact us at info@optromix.com

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Distributed Temperature Sensing at shallow depths

Distributed temperature sensing (DTS) is a state-of-the-art tool that possess an ability to monitor temperature rates over large territory and across wide temporal scales. This fiber optic technology has proved to be effective in different spheres and industries. However, despite the long field experience story, it still has its limitations and challenges apart from all the advantages. For example, when we talk about its application at shallow or deep depths.

DTS at shallow depths

The main difficulties in Distributed Temperature Sensing application

Despite all the progress that was achieved during this decade, distributed temperature sensing still meets some challenges. For example, when applied to the ocean, since dynamic oceanographic processes have a wide range of parameters, ranging from various types of turbulence to different climates, all data obtained from DTS systems fully help in understanding the dynamics of a complex ocean. However, different constraints can make modifications in time scales creating restrictions. Furthermore, there is a need for many additional advanced equipment for broad spatial resolution. That’s why it’s still complicated to use DTS in oceanography. However, now there are cases when distributed temperature sensing (DTS) is applied, for instance, in the Atlantic.

Recently, the scientists announced the first experiments on the seafloor of the Arctic sea ice with the help of the distributed acoustic sensing (DAS) system. This research has shown that fiber optic technology is effective, despite all the difficulties the scientists have faced due to the harsh environment. The system recorded a range of events that commonly applied equipment couldn’t even detect. Moreover, the DAS technology has detected the icequakes, various climate signals, and marine life.

From the other side, DTS systems can be applied in measuring surface water temperature spatial variability in lakes and rivers. The received data helps in the assessment of different factors such as estimating fish habitat and thermal inertia, the interaction between surface water and groundwater, etc. Usually, distributed temperature sensing is successfully applied in rivers and lakes with sensitive and high-resolution temperature monitoring under the wide temporal and spatial scales. Nevertheless, difficulties may arise in streams with cobbly or bedrock-lined streambeds. To avoid all the challenges, more expensive additional technologies are needed.

There are other factors that should be ensured like sensitive equipment needs protection and continuous power to work. Besides, optical fibers are delicate, they shouldn’t be bent or crimped.

How the Distributed sensing system works

Distributed sensing systems are appealing because they are able to continuously sample preserving while maintaining relatively high temporal and spatial resolution. Moreover, the accuracy indicators stay the same over a vast territory.

Distributed temperature sensors measurement allows to constantly observe temperature changes along the fiber optic cable. In this fiber optic technology the whole cable plays the role of the sensing element that measures temperature. It differs this method from the usual electrical temperature measurement. Moreover, the distributed temperature sensing is regarded as the most cost-effective and efficient system among the modern temperature measurement technologies.

The main operation principles of measurement are built on detecting the back-scattering of light:

1. 1. 1. The first type is an optical fiber that uses Raman scattering. This approach was invented in the United Kingdom. Optical fibers are usually made from doped quartz glass. When the light falls on the excited molecular oscillations, the electrons of the molecule and the electrons of the molecule start interaction. This process is called Raman scattering and results in scattered light.
    2. The second method is the Brillouin scattering-based approach. It was mostly developed in the 1990s. It refers to the scattering of a light wave by an acoustic wave because of the interaction with the acoustic phonons. Thanks to the ability of the Brillouin scattering of making both frequency down- and up-shifted light, this method can be applied whether for distributed temperature or strain sensing. It can contain both, but they can’t work at the same time.
    3. The third technique is named Rayleigh back-scattering. This is the latest development. As well as for the previously developed distributed sensors, a usual optical fiber can be used as the sensor. It allows the entire cable to be used as a single sensor, without purchasing expensive individual sensors. Scientists applied this technique, for example, for measuring distributed temperature in a nuclear reactor.

If we compare all these three techniques, each of them has its pros and cons. According to the scientists, the Rayleigh scattering demonstrates the highest rates in comparison with other types. However, it has limits in a range of fiber length. This factor is crucial for long lengths of cables’ monitoring. For this characteristic, the Brillouin scattering shows the best results. Besides, it has temperature sensitivity and good measurement time. Moreover, Brillouin scattering allows to detect distributed strain, unlike the other two methods. But usually it is applied either for distributed temperature measurement or strain. According to the data, Brillouin scattering is more often used as a substitute for Raman scattering.

DTS systems in field experiments

In accordance with the final field experiments, despite all the challenges, temperature measurements with the help of the DTS systems have been performed successfully in various environments including rivers, lakes, seas, etc. The fiber Bragg grating sensors have been applied both in fresh and sea water and demonstrated good results. Furthermore, it refers to simultaneous measurement of temperature and depth which has been impossible for previous fiber sensors.

Modern fiber optic sensors provide the parallel measurements of temperature and pressure at the same place. Besides, in comparison with other methods, fiber optic technology provides much lower power consumption. It allows the DTS systems to work longer and makes longer experiments and observation possible.

The developed fiber optic technology can be used for measurements and monitoring of the physical parameters. Moreover, it is well-placed for many cases and can be applied to various applications, such as wave and tide gauges, tsunami warning systems, etc.

All in all, we can say that distributed temperature sensing (DTS) can be successfully applied in various cases at shallow depths due to their diversity. The system can be designed and installed in accordance with the existing conditions and parameters in every single case.

Optromix is a DTS system manufacturer that provides top of the line distributed temperature sensing systems suitable for monitoring commerce networks. If you have any questions or would like to buy a DTS system, please contact us at info@optromix.com

distributed sensing systems DTS DTS systems fiber Bragg grating sensors fiber optic technology

Fiber Optic Technology for corrosion detection

It is a well-known fact that fiber optic technology has a wide range of applications in different spheres, starting from medicine and ending with 3D visualization. In particular, it is applied in the oil and gas industry where Fiber Optic Technology solves several issues, including corrosion detection.

Corrosion impact and Fiber Optic Technology

Corrosion is the deterioration of the metal because of its being under exposure to electrochemical molecules that damage its surface and lead to other worse changes. It has already become a real problem for the oil and gas industry. According to the research in 2015, the annual cost amounted to $500,000 in the US. That’s a six-time bigger than the budget for natural disasters. In fact, 33 percent of the cases occurring in the gas and oil industry are connected to corrosion.

Fiber Optic Technology for corrosion detection

That is why scientists from all over the world are looking for new ways to solve the corrosion problem by using modern fiber optic solutions. There are several methods of corrosion detection, but fiber optic technology is still considered to be one of the most cost-effective ones.

FBG sensors to Detect Corrosion

Thanks to modern scientifically developed alloys, the number of corrosion cases has declined. However, there are still challenges connected to contaminating fluids that come into contact with the metals and accelerate the corrosion process. This can definitely lead to the compromising of the structures and lives of the wells over time.

Fiber Bragg grating sensors and distributed sensing systems are considered to be some of the most cost-effective instruments that are created to locate corrosion at an early stage. Distributed sensing pipeline leak detection systems can be divided into two types: distributed acoustic sensing (DAS) or distributed temperature sensing (DTS). They are considered to be the most successful systems and are widely applied in many projects across tens of thousands of kilometers of pipelines.

That’s why FBG sensors are widely applied for corrosion detection in pipes. Fiber Bragg grating sensors transmit the data about the whole picture of the pipe’s integrity. So the corrosion can be noticed at the early stage at different levels. Thanks to the fiber optic technology, it is possible to reduce the detection period and the company losses because of the corrosion cases. Actually, the majority of gas and oil pipelines lie in urban wetlands, mountains, and forests that are the perfect environment for corrosion. And most of the pipes were not prepared for it.

That is why scientists have used the best advantages of distributed sensing to apply the FBG sensors as data lines and detectors. These FBG sensors are constantly reading the internal pipe material conditions caused by corrosion. The Fiber Bragg grating sensors read the thickness of the pipe and transmit the information to the center. They even have the ability to warn when the pipe drops below a 3 mm thickness. Moreover, FBG sensors help in detecting internal changes and events like flow constrictions and liquid accumulations. They can easily detect changes in temperature, noise, and vibration.

All in all, we must conclude that Fiber Bragg grating sensors rank among the most effective corrosion detection methods that allow solving the problem in time.

distributed sensing systems FBG sensors fiber Bragg grating sensors

Fiber Optic Solutions for 3D visualization in agriculture

Scientists have developed a new technology based on the distributed sensing system. They have found a fiber optic solution for 3D visualization in real-time that demonstrates crop root growth. Moreover, the newly developed distributed sensing system serves as radar and can be applied to measure temperature, acoustic, strain, etc.

In fact, in the 21st-century farmers agree that soil fiber optic sensors play a crucial role in agricultural development. Thanks to the data received from fiber optic sensors and other advanced technologies, they can easily develop more precise uses of water and other inputs.

Fiber Optic Solutions in agriculture

Modern fiber optic technology in agriculture

According to recent studies, the plant root directly influences crop resilience and productivity rates. For instance, deep root architecture suits better for drought resistance. Thanks to it, it is possible to keep high crop yields even in the absence of rainfalls. In contrast, shallow root structures are better for paddy fields where there is a deficiency in oxygen. To speed the crops’ adaptation to such anticipated environmental conditions, scientists had an aim to create a system that would quickly provide data in real-time on root architecture. That is why they applied modern fiber optic technology.

The whole procedure of plant roots’ visualization seems to be difficult because it requires digging. Moreover, there is still a lack of convenient and high-resolution underground imaging systems that could help in studying plant root structures.

Fiber optic sensors for root growth monitoring

With the help of fiber optic technology, scientists prototype the newest imaging device which monitors root growth underground by using distributed fiber optic sensors. During the experiments, the fiber optic sensor was attached to a soft film and transformed into a spiral. Then a distributed sensing system was put into a pot filled with soil. As a result of the tests, scientists demonstrated that the distributed sensing system is able to detect small movements within solids even when a fiber optic sensor is placed into a film structure. This fiber optic solution provides a new approach to imaging movements in the field.

Each year researchers aim to turn farming technologies into a more automated sphere. The fiber optic sensors can help in it by providing more feedback on the soil conditions, temperature, etc. This modern device based on a distributed sensing system is an important addition to the next-generation agriculture instruments. It can be applied for data-driven automation.

According to scientists, this novel method with the usage of fiber optic sensors can also have other different applications. It can suit any small-scale perturbation occurring in solids, for instance, for monitoring worms’ movements through sediments or the propagation of mushrooms in loam.

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Fiber Optic Technology as pipeline leak detection method

Fiber Optic Technology for the pipeline leak detection Special fiber optic technology can make fiber optic cable a sensing one. That solves many challenges including monitoring long units like pipelines, tunnels, or power cables. With the help of fiber optic sensors, it is more likely to find the leak in a short time. FBG interrogator sends a laser pulse through the fiber optic cable and the light comes back to the interrogator. The back scattered light delivers back acoustic, vibration, and thermal data.

Distributed sensing is widely used as an external pipeline leak detection method. Distributed sensing systems easily detect changes in temperature, noise, or vibration. Distributed sensing helps in detecting internal events, for example, liquid accumulations in gas pipelines, slugs, and flow constrictions.

Nowadays, distributed sensing pipeline leak detection software includes a wide variety of pipeline applications. The systems that apply distributed acoustic sensing (DAS) or distributed temperature sensing (DTS) are already produced in many projects across tens of thousands of kilometers of pipelines. Therefore distributed sensing systems already proved to be the most cost-effective in leak detecting.

There are standard fiber optic cables with suitable distributed sensing systems compatible with single-mode and multi-mode fibers or with a combination of them. According to the scientists, fiber optic cables with the usage of single-mode fibers are suitable for both DAS and DTS. While fiber optic cables using multi-mode fibers could enhance the DTS systems’ performance. Distributed sensing systems emphasize the detection of thermal and acoustic leak signatures. That’s why there are different types of DAS and DTS systems according to their thermal, acoustic detection capabilities, and performance requirements.

For example, a research team from South Africa is currently applying fiber optic solutions for the detection of leaks in pipelines. Scientists investigated leak detection using fiber Bragg gratings. These were applied to measure strains and temperature on pipelines and in the ground adjacent to pipelines. With the help of fiber optic technology, they could detect water leaks by burying a fiber optic cable into a pipe trench with a new pipe or place it above an existing pipe.

The scientists hope that after a number of experiments they could implement distributed sensing systems in South Africa by monitoring the pipes and delivering the data about water leaks into a leakage detection center. So fiber optic solutions would give an opportunity to fix the leak quickly without losing massive volumes of water. According to them, fiber optic technology shows great promise as a highly effective leak detection system.

distributed sensing systems DTS systems FBG interrogators fiber Bragg grating sensors fiber Bragg gratings

Distributed Acoustic Sensing (DAS) in the oil and gas industry

DAS in the oil and gas industry According to scientists, nowadays we can see newly developed distributed sensing systems that can have many appliances including monitoring of wells’ conditions in the oil and gas industry. Mostly, distributed acoustic sensing (DAS) is applied in these spheres.

The engineers have an opportunity to make decisions on operational optimization onsite with the usage of the data provided by distributed fiber optic sensors. The fiber optic technology can help in well performance improvement as well as in keeping safety at the well site. And as a result, it optimizes production from oil and gas wells. In comparison with distributed sensing, there is no such method that could provide such quality and extent of detail about physical conditions.

Mostly, distributed acoustic sensing (DAS) is produced to record fluid and gas flow signals, listen to hydraulic fracturing-related signals, etc. Distributed sensing systems trace changes in acoustic vibrations along the entire length of a fiber optic cable in real-time. In the fiber optic cable, there are thousands of detection points at minimal spatial intervals. Compared to the usual sensing systems, distributed sensing does not rely on discrete sensors at predetermined points. Distributed sensing system uses the whole fiber optics itself as a sensing unit.

Therefore, fiber optic technology is suitable for those who want to apply environmental monitoring in sensitive geologic operations. Thanks to the length of the fiber optic cable and its working ability in severe environmental conditions for long, it is quite popular for such use. The down hole fiber optic sensor application provides for oil and gas wells, flow-back operations, geothermal wells, etc.

The ability of measurement along the complete length of the fiber optic cable can be applied for many other applications like the characterization of contaminated bedrock aquifers and monitoring of geologic carbon sequestration projects. In addition to that, distributed sensing systems can also register the conditions of the near-wellbore area of subsurface rock formations.

DAS system manufacturers always have an aim of making their fiber optic solutions better. For the DAS systems, it is the regulation of acoustic and vibratory noise sensing. The ambient noise is always in sites and should not be measured.

That is why the next scientific goal for DAS technology is the creation of a portable vibration isolation system to maximize the distributed acoustic sensing system’s dynamic range.

Optromix is a DAS system manufacturer that provides top-of-the-line distributed acoustic sensing systems suitable for monitoring commerce networks. If you have any questions or would like to buy a DAS system, please contact us at info@optromix.com

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