Category: Distributed Acoustic Sensing (DAS)

Fiber-optic distributed acoustic sensing or DAS is a highly effective technique that allows monitoring highways, railroads, and pipelines. Moreover, today it is possible to provide lower-cost communications network surveillance and management due to DAS ability of constant gapless monitoring.

The thing is that the world economy requires a reliable global network of highways, railroads, and pipelines for the transportation of people, products, and resources across countries and continents. Also, fiber-optic communication cables including spare optical fiber are often used for their continuous, gapless monitoring.

Distributed acoustic sensing is a fiber-optic sensing technology that is quite “young”, about ten years ago. Since then, the technology is used not only in the laboratory but outside in several real-world applications.

The first main application of DAS is a new type of fiber optic security sensor for early detection of intruders. Then, distributed acoustic sensing became used in the oil and gas industry for the following aims:

1. control of the effectiveness of hydraulic fracturing;
2. production flow control;
3. control of borehole seismic activity.

The unique ability of the DAS system to control quite long fibers that are already in place allows using distributed acoustic sensing for pipeline monitoring that is the today main field of DAS application as well as control of highways and railroads located next to optical fiber routes.

It should be mentioned that all these applications use the same key platform technology. The principle of DAS operation is based on signals that can be analyzed in real-time for detection, location, and classification of events. Then the obtained information that can be in different formats is transmitted to an operator.

Herewith, all distributed acoustic sensing systems use a technique called coherent optical time-domain reflectometry (C-OTDR) that is highly efficient for all fields of application. Now it is possible to detect different anomalies such as falling rocks along the tracks by the DAS system.

Nevertheless, DAS has the biggest influence in the signaling area, for example,  distributed sensing helps to manage trains by control of their accurate position and motion in real-time. The technology enables to reduce journey times while increasing rail capacity and improving safety.

Of course, the distributed acoustic sensing system continues improving and the improvement will provide quantitative measurement with improved sensitivity and higher spatial resolution on longer lengths of the sensing fiber in the future.

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

Today transport networks are the essential element of any major city. A huge amount of vehicles causes a reduction in road space, often accidents and traffic jams. Unfortunately, our present traffic systems cannot manage with the increased flows, for example, only the past two decades has seen an 84% increase in the number of cars. This became the main reason for the development of a new approach to traffic monitoring.

The possible solution is the use of distributed acoustic sensing or DAS by fiber optic cable networks. Herewith, it should be mentioned that fiber optic networks suggest two main advantages over other potential smart transport technologies:

• the diffusion of fiber optic cables, to be precise, they cover almost all parts of cities and road infrastructures.
• no need for their installation because fiber cables are already in place. That is why it is not necessary to dig up the streets, install new cameras, or fit point sensors.
• no need for vast spending programs to deploy new technology.

The principle of work is based on the ability of all traffic to generate acoustic or seismic data. In addition, some specific activities, for example, incidents create certain acoustic signatures and these acoustic vibrations pass through fiber optic cables. Thus, distributed acoustic sensing allows interpreting the acoustic information to recognize, determine, and track these signatures for traffic flows and public transport infrastructure monitoring in real-time.

The DAS systems enable to analyze traffic speed and density, detect a traffic jam, and identify disruptions like broken-down vehicles. The most important thing is that the DAS technology opens the opportunity for city authorities to make dynamic adjustments to transport infrastructure that will be necessary to keep cities moving now and in the future.

For example, in the case of an accident or intense level of traffic, the DAS system is able to adapt quickly traffic controls and redirect road traffic to balance overall vehicle flows and avoid a traffic jam. Nevertheless, the whole potential of the DAS technology is not explored yet but at the present time, it is tested in Canada.

The novel distributed acoustic sensing combine monitoring of the public tram system, public road networks, and even autonomous vehicles to create a complete picture of the transport network situation in the city. Then, the obtained information is transmitted into an app for citizens where they can see the road traffic to optimize their own journeys. Finally, it is planned that fiber optic sensing solutions will soon make intelligent transport systems cheaper, with less disruption than alternative approaches. 

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

Distributed Acoustic Sensing (DAS) systems are based on fiber optic technology, which allows the systems to be used with extreme operating conditions, for example, extremely high or low temperatures, physical space limitations, unique measurement requirements, etc. DAS system consists of a distributed acoustic sensors that can be either mounted on the object or buried at a certain distance from it, In-cab InGound Stainless Steel Tube, and software that allows remote control and status monitoring.

The areas of DAS systems use include:

• in-well monitoring for leakage detection and activity control;
• perimeter security, for example, the security of a hotel;
• vibroacoustic monitoring of oil wells that allows us to find out the points of columns and packers leakage, determinate the fluid’s inflow, and the hydraulic fracturing intervals.

Now Distributed Acoustic Sensing systems are the best way for the intrusion and disruption detection of overhead power lines to reduce theft cases and costs. Unfortunately, today power line theft and tampering remain a major problem all around the world. Also every year the industry loses billions of dollars only in electricity theft.

Theft and tampering within the energy supply sector is a serious problem because it creates energy supply breaks and operational losses for supply companies and national grids. Traditional methods of resolving the issue (whether due to power or metal theft) are extremely time-consuming, inefficient, and expensive. In the majority of cases, DAS is the only solution to the main obstacle that is detecting and identifying the occurrence of theft events.

The fiber optic DAS system is a cost-effective method to identify and reduce tampering levels. The fiber optic monitoring allows identifying tampering with overhead lighting and distribution poles that are connected via a fiber optic cable. Moreover, real-time identification of thefts and tampering with the help of fiber optic cables are already in place. DAS system detects any underlying disturbances because all the surrounding environmental noises are filtered out.

The advantages of fiber optic distributed acoustic sensing systems include:

• Identification of the precise damage location;
• Tampering information pass onto security systems for the immediate action;
• Broadcast alert to the company via email or SMS.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. Optromix creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. The range of services includes research programs, interpretation reports, layout design, system software modeling, commissioning, user training, real-time data transition, equipment supply, ground part installation, engineering, and technical support. If you are interested in DAS systems and want to learn more, please contact us at info@optromix.com

Fiber optic products are progressively being deployed in many upstream and midstream applications. Nowadays fiber optic equipment is regularly used to provide high bandwidth telecommunications and infrastructure for SCADA (Supervisory Control and Data Acquisition) and is being used more and more to sense pressure, temperature, and strain along buried onshore and subsea pipelines and downhole. Pipeline leakage and intrusion detection continue to be a difficult issue because existing leak detection methods and the traditional methods of guarding pipelines have proven inadequate in the prevention of leaks and deferring third-party intrusion into pipelines and plant facilities.

Distributed Acoustic Sensing (DAS) systems based on fiber optic products are actively used for both sensing and telemetry. Each of the 4,000 independent, simultaneously sampled channels, of which the above systems consist, can be used to detect and locate activity within the vicinity of the pipeline. Also, that channels can be used to classify the type of activity through sophisticated acoustic signal processing.

Distributed Acoustic Sensing systems are very simple systems for providing total monitoring protection over large distances. DAS utilizes sensing cables, that are based on standard fiber optic cables, to obtain a measurement profile along the entire length of the sensing cable at intervals ranging from 3-10 m, depending on the physical size of the system. There is no specialized sensing point required.

There are three basic types of DAS systems utilized for fiber optic measurements:

• Rayleigh-based systems
• Raman-based systems
• Brillouin-based systems

Depending on the frequency of the signal that is derived, this nomenclature is analyzed. DAS systems are ideally suited to monitoring pipelines for the third-party intrusion. Recent developments in the fiber optic products field have also highlighted the ability of the system to track pig runs, provide seismic data during earthquakes, and detect gas leaks in buried pipelines.

Optromix is a fast-growing seller of such products from the fiber Bragg grating (FBG) line of products: fiber Bragg grating sensors, FBG interrogators and multiplexers, and, of course, Distributed Acoustic Sensing Systems (DAS). Our major goal is to deliver the best quality of fiber-optic sensors to our clients. Optromix creates and supplies a broad variety of excellent fiber-optic solutions for the monitoring of various facilities all over the world. The use of Distributed Acoustic Sensing technology in downhole applications (all using the same optical fiber cable) gives a continuum of benefits that are distributed to the flow profiling and the condition monitoring. Distributed acoustic sensing systems can be retrofitted to existing installations of permanent in-well fiber optics-based monitoring systems with the addition of surface equipment. New installations of DAS systems are also possible and have already been performed.

If you are interested in DAS systems and want to learn more, please contact us at info@optromix.com

Distributed Acoustic Sensing (DAS), the rapidly evolving optical fiber sensor technology for permanent geophysical monitoring uses fiber optic products to allow acoustic frequency strain signals to be detected over large distances and in a harsh environment. The principle of Distributed acoustic sensing is based on changes in the intensity of light reflections caused by sound waves radiating against a single-mode fiber optic cable. These changes can be detected and used to obtain valuable information. The last decade is marked by growth in the distributed acoustic sensing market. The growth is stimulated by drivers such as the ability of the systems to operate in harsh working environments. Furthermore, Das systems based on the fiber optic equipment are not susceptible to electromagnetic interference and resistant to corrosion in humid conditions. Another driver for the DAS market is the ability of DAS technology to provide key data which helps to optimize oil and gas operations. DAS system is so sensitive that it can detect even a low-flying drone passing overhead, vandals damaging a railway line, or someone probing the ground trying to find a pipeline from which to steal oil.

Walk-away data, which can be obtained with the help of the distributed acoustic sensing system, yield images that are nearly equivalent to images from traditional borehole geophones in terms of signal to noise ratio and resolution. Distributed acoustic sensing system can be used to monitor all sorts of sensitive locations, from oil and gas pipelines to railway tracks, military bases, and international borders because such a system allows underground fiber optic devices to be converted into a giant string of microphones. Nowadays DAS capabilities are in use in the oil, gas, and border protection businesses. Permanently installed fiber optic infrastructure based on fiber optic devices will enable low-cost non-intrusive geophysical monitoring. Also, it should be noted, any single-mode fiber can quickly be turned into a series of listening fiber optic devices using distributed acoustic sensing with minimal fiber work at either and of the monitored fiber section. In addition to this, a distributed acoustic sensing system is capable of creating a hydraulic fracturing or “fracking” that is very effective at releasing natural gas and oil trapped in rocks. This system works by sending sharply defined pulses of laser light down the cable: high-speed signal-processing techniques are used to analyze instantly what the sound is likely to be. Various seismic sensors can be used to monitor the fracking process, from test bores drilled nearby, but it is a costly and tricky process. Also, the Distributed acoustic sensing system can be used to monitor sounds coming from below ground, in particular, those produced by the water, sand, and chemicals pumped under high pressure to fracture rock during fracking.

The DAS technique relies on a phenomenon known as Rayleigh scattering, named after 19th-century British Lord Rayleigh, who discovered it. The first DAS operation was performed by Shell in 2009. Since then, this technique has been improved and widely tested in various field situations including the VSP (Vertical Seismic Profiling), microseismic measurements, well and reservoir surveillance, hydraulic fracturing monitoring, and diagnostics. In addition, Shell and other oil companies are using the DAS system to monitor their fracking. It uses fiber optic devices inserted into a wellbore to build up an acoustic picture of the fracking fluid going into the rock at multiple levels. The fracking process can be constantly adjusted so that it runs in the most efficient way by having a clearer idea of how much fluid is going where. The DAS system is the ideal solution for the detection of this fluid and its pathways.

The DAS market is expected to be worth USD 440,2 Million by 2020. The major vertical in this market is the oil and gas industry, followed by infrastructure and fire detection. In oilfield services, DAS is used in evaluation, completion, and production activities, and helps in cost optimization. The geographic analysis means America’s DTS manufacturers as leaders on the market. Asia Pacific (APAC) region is expected to grow the fastest during the forecast period.

Distributed acoustic sensing systems can be retrofitted to existing installations of permanent in-well fiber optics-based monitoring systems with the addition of surface equipment. New installations of DAS systems are also possible and have already been performed.

If you are interested in DAS systems and want to learn more, please contact us at info@optromix.com

A new generation of in-well monitoring technologies that are being characterized under the Acoustic Energy sensing banner has been recently developed. There are multiple monitoring techniques that may be classified under the same umbrella, like disturbance or vibration event monitoring; however, the distributed acoustic monitoring (DAS) technique has become popular for in-well monitoring applications.

Since the development of fiber optic technology, the fiber optic-based monitoring systems have been used in applications with extreme operating conditions, i.e. extremely high or low temperatures, physical space limitations, unique measurement requirements, etc. The electrical/quartz sensing technology has always had a temperature limitation of 150°C, which does not allow the use of these systems in industries and applications where high temperatures are often present. DAS systems, on the other hand, are based on fiber optic technology, which allows the systems to be used under much higher temperatures.

A distributed acoustic sensing system allows its user to listen to the acoustic field at every point along the standard telecom single-mode fiber optic cable, which can be several kilometers in length. The fiber optic cable is deployed in a well, where the system monitors its condition and registers production-relevant events. The optic fiber cable used in such a system can be loaded with many sensors, e.g. with a spatial resolution of 1 meter there will be 10.000 synchronized sensors along a 10.000-meter fiber optic cable. Distributed acoustic sensing systems utilize a novel digital optical detection technique to catch the full acoustic field with great precision: amplitude, frequency, and phase over a wide dynamic range. The main advantage of a DAS system is its ability to catch the acoustic field at every point simultaneously.

DAS systems use the combination of backscattered light and advanced signal processing to segregate the fiber into an array of individual microphones.

Traditionally, distributed acoustic sensing systems have been used in the defense and security industries; however, DAS systems are quickly becoming one of the most effective and cost-efficient ways of in-well monitoring, for example, oil and gas leakages. Another promising field of application of the DAS systems is in the area of hydraulic fracturing of tight-sand and shale-gas reservoirs. The first downhole field trial of a DAS system was conducted in 2009. The technology is sufficiently reliable and sensitive to be used during the fracture-stimulation treatment to monitor the in-well activities.

Distributed acoustic sensing systems can be retrofitted to existing installations of permanent in-well fiber optics-based monitoring systems with the addition of surface equipment. New installations of DAS systems are also possible and have already been performed.

If you are interested in DAS systems and want to learn more, please contact us at info@optromix.com

The development of modern technology and an ever-increasing need for larger volumes of production drive the optical fiber technologies forward towards more precise measurement. Optical fiber technology has been rapidly developing for the past 30 years and now approaches the theoretical limits in terms of attenuation and precision manufacturing. The refinements have been taken advantage of in many non-transmission applications, where optical fiber sensing has come to the forefront of numerous industries and applications.

There are numerous embodiments of fiber optic technologies in modern industries, that include distributed temperature sensors, FBG strain sensors, FBG strain sensors, FBG pressure sensors, FBG interrogators, FBG multiplexers, etc. One of them – Distributed Acoustic Sensing (DAS) – provides near real-time measurements by using optical fiber by taking advantage of its low attenuation and long reach. The dielectric nature of distributed acoustic sensing and its immunity to radiofrequency and electromagnetic interference also present an important benefit of DAS to multiple applications.

The technology behind distributed acoustic sensing relies on coupling coherent laser energy pulses into an optical fiber and analyzing naturally-occurring Rayleigh backscatter. As light travels from the input to the distal end, it interacts with fiber, which causes a small amount of light to backscatter. The light that returns to the input end is detected and analyzed. Acoustic waves interact with the material that constitutes the fiber create changes in the refractive index. The changes in the refractive index have an effect on the backscatter characteristics that become detectable for the system. The time-domain techniques are then used to determine the location of the event, which provides fully distributed sensing with a resolution of 1 meter or less.

Distributed acoustic sensing has been found useful and necessary for many different applications, some of which include:

1. Oil and gas monitoring;
2. Perimeter security;
3. Wells monitoring;
4. Powerlines monitoring.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line: fiber Bragg grating sensors, FBG interrogators, and multiplexers, Distributed Temperature Sensing (DTS) systems. We create and supply a broad variety of top-notch fiber optic solutions for the monitoring of various facilities all over the world.

We provide a distributed acoustic sensing system that is much less expensive than other analogous systems present on the market. If you are interested in Optromix distributed acoustic sensing system, please contact us at info@optromix.com