We are the independent provider of fibre optic-powered data solutions
EcoGeo is an engineering center for fiber-optic monitoring systems. Fiber-optic temperature, acoustic and geotechnical monitoring is used for real-time data acquisition and processing, where the distributed sensor is the optical fiber itself. Integrated fiber optic-based monitoring solutions provide unparalleled accuracy for fast and high-quality decision-making in industries such as mining, oil and gas, infrastructure, environment, and earth science.
Sectors
- Mining industryMonitoring of hydraulic structures (HS)
Measuring process flows at mining and processing plants
Microseismic monitoring
Ground and borehole seismic monitoring - Oil and gas industryFlow profiling in the well
Well integrity monitoring
Hydraulic stimulation monitoring
Seismic well monitoring - InfrastructureMonitoring of dams
Trunk pipelines monitoring
Geotechnical monitoring (tunnels, railways, roads, bridges)
Process monitoring (reactor vessel, tanks)
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Innovative technologies
Distributed fiber optic monitoring is a technology that provides continuous, real-time measurements along the entire length of a fiber optic cable. In contrast to traditional technologies, which are based on discrete sensors measuring at predefined points, distributed fiber optic monitoring uses optical fiber as a distributed sensor. The optical fiber is the sensing element without any additional transducers on the optical path. The requestor works according to the radar principle: it sends a series of pulses into the optical fiber and registers the return of the natural scattered signal over time. In doing so, the distributed sensor takes measurements at all points on the fiber. Because the fiber is a sensor, it is also an economical method that can be easily deployed even in the harshest and most unusual conditions.
Distributed fiber optic monitoring is used to collect temperature, acoustic and strain data.
The optical fiber is made of pure glass (silica) as thick as a human hair. It consists of two parts: an inner core and an outer shell. The shell is a glass layer consisting of glass with a lower refractive index to support the direction of light inside the core. For protection and ease of handling, both parts are coated with one or more layers of primary polymer coating.
There are two basic types of optical fibers according to communication application standards: single-mode for long-range communications and multimode for short-range communications. Multimode fibers have a larger core (45 to 50 microns) than single-mode fibers (8 to 10 microns), which allows more light modes to be distributed.
Distributed fiber optic monitoring is used to collect temperature, acoustic and strain data.
The optical fiber is made of pure glass (silica) as thick as a human hair. It consists of two parts: an inner core and an outer shell. The shell is a glass layer consisting of glass with a lower refractive index to support the direction of light inside the core. For protection and ease of handling, both parts are coated with one or more layers of primary polymer coating.
There are two basic types of optical fibers according to communication application standards: single-mode for long-range communications and multimode for short-range communications. Multimode fibers have a larger core (45 to 50 microns) than single-mode fibers (8 to 10 microns), which allows more light modes to be distributed.
The typical diameter of an optical fiber is 125 microns, which increases to 250 microns if we consider the thickness of the standard acrylate coating. Multimode fibers are typically used for temperature sensing, while single-mode fibers are primarily used for distributed acoustic or strain sensing. Although temperature and acoustic sensors can be used with both single-mode and multimode fiber, the performance of the temperature system is optimized when it is used with multimode. Acoustic sensor performance is optimized with single-mode fiber.
Fiber optic cables can contain multiple fibers, which can be of the same type or a combination thereof. The design of the cable depends on installation, operation, and application conditions.
Fiber optic cables can contain multiple fibers, which can be of the same type or a combination thereof. The design of the cable depends on installation, operation, and application conditions.
How does distributed
temperature measurement DTS work?
temperature measurement DTS work?
The basic principle of DTS is temperature measurement based on Raman scattering combined with optical time domain reflectometry (OTDR). A short light pulse is triggered into the fiber. The forward propagating light generates Raman light scattered backward at two different wavelengths from all points along the fiber. The wavelengths of Raman light back-scattered differ from those of light propagating forward and are called "stokes" and "antistokes. The amplitude of the stokes and antistokes light is tracked, and the spatial localization of backscattered light is determined based on knowledge of the speed of propagation within the fiber. The amplitude of the stokes light is very weakly dependent on temperature, while the amplitude of the antistokes light is strongly temperature dependent.
The temperature profile in an optical fiber is calculated from the ratio of the amplitude of the stokes and antistokes light. A typical system is characterized by spatial and temperature resolution. Spatial resolution is the minimum distance from the sensor to measure the jump in temperature along the optical fiber. Temperature resolution is a measure of the accuracy of absolute temperature determination.
Temperature resolution depends on the measurement time and the repetition rate of the trigger pulses. Laser pulse energy and duration are precisely controlled and optimized for maximum measurement length to provide the best available temperature resolution within acceptable accuracy limits. As sampling time increases, temperature resolution improves and the resulting temperature values become more accurate.
The temperature profile in an optical fiber is calculated from the ratio of the amplitude of the stokes and antistokes light. A typical system is characterized by spatial and temperature resolution. Spatial resolution is the minimum distance from the sensor to measure the jump in temperature along the optical fiber. Temperature resolution is a measure of the accuracy of absolute temperature determination.
Temperature resolution depends on the measurement time and the repetition rate of the trigger pulses. Laser pulse energy and duration are precisely controlled and optimized for maximum measurement length to provide the best available temperature resolution within acceptable accuracy limits. As sampling time increases, temperature resolution improves and the resulting temperature values become more accurate.
The DTS samples data at a fairly high speed, allowing data to be recorded at intervals as small as 12.5 cm with a temperature resolution of only 0.01° C. There is a trade-off between temperature resolution, spatial resolution, measurement time, and fiber length. Spatial resolution and averaging time are user-defined in the software and can be changed by the operator as needed.
How does the DAS intelligent
distributed acoustic sensor work?
distributed acoustic sensor work?
The DAS technology measures the acoustic signal at all points on a multi-kilometer fiber as if it were a string of microphones. The intelligent distributed acoustic sensor works by feeding a pulse of laser light into the optical fiber. As this pulse of light travels along the optical path, interactions within the fiber that result in light reflections, known as backscattering, are determined by tiny deformations within the fiber, which, in turn, are caused by localized acoustic energy. This backscattered light returns along the fiber to the DAS, where it is sampled. Time-synchronization of the laser pulse allows the backscatter event to be precisely matched to the distance along the fiber.
Once the light pulse has traveled to the end of the fiber and any reflections have returned to the poller, the fiber can be considered "dark," and a subsequent laser pulse can be injected without risk of interference. For each laser pulse, the entire fiber distance is measured at each point along its length, usually every 1 meter. The result is a continuous acoustic sample along the entire length of the optical fiber without crosstalk and with a frequency range from milligahertz to over 100 kHz and a dynamic range of over 120 dB. DAS is a true acoustic sensor because it accurately reproduces sound in phase, frequency and amplitude. This capability is critical for advanced processing techniques used in many applications, and is not typical of some DAS systems currently on the market, which may not provide the amplitude stability or phase accuracy required for advanced processing.
Once the light pulse has traveled to the end of the fiber and any reflections have returned to the poller, the fiber can be considered "dark," and a subsequent laser pulse can be injected without risk of interference. For each laser pulse, the entire fiber distance is measured at each point along its length, usually every 1 meter. The result is a continuous acoustic sample along the entire length of the optical fiber without crosstalk and with a frequency range from milligahertz to over 100 kHz and a dynamic range of over 120 dB. DAS is a true acoustic sensor because it accurately reproduces sound in phase, frequency and amplitude. This capability is critical for advanced processing techniques used in many applications, and is not typical of some DAS systems currently on the market, which may not provide the amplitude stability or phase accuracy required for advanced processing.
A key distinguishing feature of the DAS is its ability to measure equally well on both single-mode and multimode fiber, allowing the DAS to be retrofitted on an existing multimode fiber installation or to use multimode DTS cables to perform a full range of DAS services.
Environmental Geophysics LLP
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+7 (777) 671-30-55 info@ecogeo.kz
Address
Kazakhstan, Astana city, Almaty district, 23-15 street, 11/3
+7 (777) 671-30-55 info@ecogeo.kz
Address
Kazakhstan, Astana city, Almaty district, 23-15 street, 11/3