Fiber optic well monitoring

The well integrity has become a critical concern after recent events in the oil industry, such as oil spills. The interaction of a salt layer with the cement and casting for Pre-salt wells is a concern for fiber optic well monitoring and the structural integrity of the well. The development of continuous monitoring tools for well structural integrity is an ongoing task for the oil industry.

Continuous fiber optic well monitoring has the advantage of allowing the quantification of the time needed for an event. Casting integrity logging operations may provide information regarding the damage location, however, the time in the life of the well when the damage happened or the process of the well degradation can not be determined. The logging operations can only provide information on the condition of the well at a particular time, not continuously. Continuous monitoring can help to correlate well damage and events that could be the cause of the damage, like outside intervention, allowing for corrective and preventive measures to take place.

The two main parameters that need to be measured are strain and temperature. The strain in fiber optic well monitoring can indicate the strain in the casting that is caused by the creep of the salt layer. Distributed temperature sensing may be used to indicate the positioning of the cement slurry, diagnose the curing process, and indicate the cementing failures.

The sensors need to be installed outside the production casing of the production liner. The size of the sensors, therefore, is required to be small. DTS sensors, in particular, are compact and are easy to install onto any surface. However, the mounting process of the sensors needs to be delicate as the casing properties may degrade. Fiber optic well monitoring solutions shouldn’t be intrusive as the sensors could potentially cause issues, like poor isolation.

Optromix, Inc. is a U.S. manufacturer of innovative fiber optic products for the global market, based in Cambridge, MA. Our team always strives to provide the most technologically advanced fiber optic solutions for our clients. Our main goal is to deliver the best quality fiber optic products to our clients. We produce a wide range of fiber optic devices, including our cutting edge customized fiber optic Bragg grating product line and fiber Bragg grating sensor systems. Optromix, Inc. is a top choice among the manufacturers of fiber Bragg grating monitoring systems. If you have any questions, please contact us at info@optromix.com

Fiber bragg grating sensors for structural health monitoring in harsh conditions

Piezoelectric transducers have been traditionally used in structural health monitoring. These devices convert pressure to an electric voltage. The transducers are typically reliable in normal working conditions, however, they become less accurate in harsh environments, like high temperatures – over 300 degrees Celsius – or highly corrosive environments.

With the development of laser technologies the popularity of fiber Bragg grating sensors have been increasing due to their numerous advantages over traditional means of measuring strain, pressure, and temperature: 1) FBG sensors work reliably under very high temperatures because of the optical fiber material – fused silica; 2) fiber Bragg grating sensors are immune to electromagnetic interference; 3) the sensors are not susceptible to corrosion; 4) FBG sensors are very small and can be easily mounted on any surface. The development of fiber-optics technology will enhance structural health monitoring in harsh conditions, such as nuclear power plants and modern superheaters.

The following types of FBG sensors are used in structural health monitoring:

  1. FBG temperature sensors;

The main advantages of fiber Bragg grating temperature sensors are their reliability and accuracy under high temperatures, absolute temperature measurements, fast response, immunity to electric sparks. The fast response rate is particularly useful in cases where temperature shifts are extreme.

2. FBG strain sensors;

FBG sensors are the best strain sensors at the moment due to multiple advantages that are inherent to all FBG products. These sensors can determine structure parts that are stressed.  

3. FBG displacement sensors.

Fiber Bragg grating displacement sensors can detect shifts in structures and the appearance of cracks.

There are many applications of fiber Bragg grating sensors for structural health monitoring. For example, one of the possible uses of FBG sensors is pipeline monitoring. P19 pipelines, that are used in the power industry, are usually used to transmit corrosive high-temperature, high-pressure steam. The integrity of the pipes may deteriorate over time leading to eventual failure of the steam transmitting system.

If you would like to purchase FBG (Fiber Bragg Gratings) sensors, please contact us: info@optromix.com or +1 617 558 98 58

Fiber Bragg grating sensors in chemical sensing

Chemical sensing is a developing field of fiber Bragg grating sensors. It is involved in the control of chemical processes, oil recovery, environment quality improvement. There are several factors that play a role in the implementation of chemical sensors – suitability for remote sensing, sensitivity, low costs, selectivity, ability to work consistently in harsh environments. The oil and gas applications require sensors that can withstand high temperatures and pressures, and environmental sensors must have a wide coverage area and limited signal fluctuations.

Fiber Bragg grating sensors have been used in numerous applications, including aircraft monitoring, structural health monitoring, strain, and temperature measurements. In the last decade, FBG sensors have been implemented as chemical sensors due to their ability to withstand high temperatures, immunity to electromagnetic interference, and the absence of electronics.

The main principle of FBG sensors for applications in chemical sensing is based on the axial strain of the fiber. The chemicals that surround the fiber causes it to shift and deform. The strain caused by the presence of a particular chemical causes the spectral pattern of reflected light to change; the shift in reflected wavelength is observed. To monitor the shift in wavelength FBG interrogators are used. The data gathered by the interrogator can then be converted to environmental concentrations.

The key component of fiber Bragg grating sensors for chemical sensing is a highly sensitive coating. The coating should be stiff and adhere easily and firmly to the glass fiber. Most often the coating is based on polymers. However, the coating needs to have a high modulus of elasticity that remains high at high temperatures and during analytes absorption. Most polymers are restricted by temperature due to softening and material relaxation.

Some ways of FBG sensors polymer coating include:

  1. improved coating processing;

The improvement of the coating process, like improved adhesion, may aid in the reduction of material relaxation and shifting. The glass fiber may be treated before the application of polymer coating for improved adhesion.

  1. improved data processing;

The use of two different coatings that respond in equal, but the opposite manner to environmental changes. The combination of the two responses limits the temperature drift.

  1. improved material properties.

Alternative coatings, like ones based on ceramic materials, may expand the temperature application range.

Optromix, Inc. is a U.S. manufacturer of innovative fiber optic products for the global market, based in Cambridge, MA. Our team always strives to provide the most technologically advanced fiber optic solutions for our clients. 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. If you would like to purchase FBG sensors, please contact us at info@optromix.com

FBG strain sensors in structural health monitoring

Fiber Bragg grating sensors are used over conventional sensors in structural health monitoring based on a number of advantages they provide:

  • FBG sensors are more stable;
  • fiber Bragg grating sensors are more durable, namely, they don’t rust;
  • FBG sensors can be highly multiplexed;
  • the sensors can be used in highly explosive atmospheres, like natural gas or oil.

These features are desirable for the health monitoring of complex structures. FBG structural health monitoring systems are essential in the design of smart buildings. The FBG sensor systems help to ensure building safety and performance. The systems are of particular use for buildings situated in earthquake-prone zones.

The mechanism behind FBG sensors allows to monitor complex structures based on the measurements of the wavelength of the reflected light; its wavelength changes under the influence of pressure, building incline, etc. Due to the fact that a single FBG sensor reflects a narrow region of the light, it is possible to multiplex them, which provides higher data accuracy. However, the number of FBG elements should be carefully designed and spaced in accordance with the range and bandwidth of the input light source.

The FBG strain sensors are fragile on their own, therefore they need to be placed on a base of some kind to protect them from outside physical influence. Usually, the sensors have a metal protective cover that prevents damage to the sensors from environmental factors. The sensors are then welded or glued to a structural member. FBG strain sensors, or FBG deformation strain sensors, can be used in both steel and concrete structures; they offer high accuracy and resolution. The measurements received from the sensors are often used to detect the behavior of structural materials under different environmental influences. The detection of segments that are stressed is essential for proper maintenance of the building and its structural parts and prevents premature aging and failure of these structures.

FBG strain sensors may also be used in the monitoring of tunnel ribs, pipelines, ship hulls, etc. Their high accuracy, easy installation, and compact nature provide a wide area of applications.

Optromix, Inc. is a U.S. manufacturer of innovative fiber optic products for the global market, based in Cambridge, MA. Our team always strives to provide the most technologically advanced fiber optic solutions for our clients. If you would like to purchase Optromix FBG Strain Sensors, please contact us: info@optromix.com or +1 617 558 98 58

Fiber optic aircraft monitoring

Fiber optic sensors are used in aircraft structural health monitoring as they possess numerous advantages for real-time monitoring like immunity to electromagnetic interferences, low weight, small size, and high bandwidth. The latter allows multiple sensors to be used simultaneously within the same system.

It is anticipated that air traffic will grow significantly in the forthcoming years. Most modern airplanes make use of composite materials instead of conventional aluminum alloys, therefore durability and safety issues arise due to the complexity of composite materials. The different materials that compose them react differently to different environmental changes, which results in unpredictable behavior. The systems that enable the opportunity to monitor the aircraft in real-time are essential for safety and reliability improvement and reduction of maintenance costs. Fiber optic aircraft monitoring is a promising way of improving efficiency and operation costs.

FBG sensors have already found a wide range of applications. Fiber Bragg grating sensors are used in the monitoring of composite structures during on-ground aircraft testing; some airplanes are already equipped with FBG sensors that provide real-time data during a flight. The data provided by the sensors is valuable for local damage detection, and fiber optic aircraft monitoring has proven to be beneficial to the field. The integration of FBG sensors into the composite materials would enable the monitoring of the material during its whole life cycle.

Among multiple types of sensors optical sensors, namely FBG sensors, are of particular interest for aircraft monitoring due to their high sensitivity and durability. The multiplexing capability of FBG sensors reduces the weight of the wiring. Moreover, fiber Bragg grating sensors are significantly less expensive than other sensors.

However, the technology is not fully developed yet and more effort is still needed to bring it to a mature level. Among the challenges of fiber optic aircraft monitoring is the development of methods to monitor structural parameters over large structures.

Optromix, Inc. is a U.S. manufacturer of innovative fiber optic products for the global market, based in Cambridge, MA. Our team always strives to provide the most technologically advanced fiber optic solutions for our clients. If you would like to buy FBG sensors, please contact us at info@optromix.com