There is no possibility to generate an electric spark or electric shock (this is very important particularly in medical applications). They can be designed in a form of very small and flexible device. In comparison with the electrochemical sensors they do not require any reference electrode or cell. Many of the advantages of FOCS are due to the characteristics of fiber optics. Light sources (light emitting diodes, laser diodes, lamps etc.), photodetectors (photodiodes, photomultiplier tubes etc.), connectors and optical fibers can be easily adapted for sensing purposes.įiber optic chemical sensors (FOCS) can be utilized in harsh and hardly accessible places. Their development has been stimulated by advances in optoelectronic technology mainly for applications in telecommunication. Fiber optic sensors can measure physical or chemical quantities. Wróblewski, in Studies in Surface Science and Catalysis, 1999 1 INTRODUCTIONįiber optic sensors and systems are finding increasing number of applications in industry, environmental monitoring, medicine and chemical analysis. The increasing use of optical fibres in the transmission link will inevitably change the way security installers work.Īt the present point in time the use of optical fibres may well be seen as a specialist subject, but the importance of their applications and uses should certainly still be understood.Ī. The intruder alarm industry at present may well be in its infancy with respect to optical fibres, but their use will surely become more established in the future.
ADVANTAGES OF OPTISYSTEM FREE
This makes the unit essentially free from adjustment. This is performed in the receiver units, and the same electronic circuit ensures that the signal level is adjusted throughout the life of the equipment. This is carried out by a process called automatic gain control (AGC). Therefore, rather than having several controls to balance the signal after transmission, all that is needed is simple amplification. Gerard Honey, in Intruder Alarms (Second Edition), 2003 Setting upįibre optic systems, unlike copper wire-based systems, attenuate the signals equally irrespective of frequency. During field applications, the further analysis shall be performed to choose the deployment methods since they all have advantages or disadvantages within each other (which is further related to cost and calibration of the systems). In terms of the deployment of the fiber, there are four primary methods single end straight fiber, single end straight fiber with downhole temperature gauge, partially returned fiber, and double ended fiber. In this situation, the capillary tube cannot be pulled easily from the well. The permanent application can be done by installing the fiber optic line behind the casing while cementing the well. The second option could be to use a stainless-steel capillary tube which is strapped outside of the production casing and run the fiber optic line into this tube. The first option is to run the fiber optic line through coiled tubing and leave it in place for continuous and periodic measurements. There are various ways of using semipermanent applications. In a retrievable installation, fiber optic line is run into the well using a steel capillary tube which has a diameter of about 3 mm. These can be categorized as retrievable, semipermanent, and permanent type installations. There are various options in fiber optic distributed sensor installations in oil and gas wells. Example of protection methods for using only one multimode fiber line (A) or one multimode fiber line with two single mode or other types lines (B). Protection of fiber lines used in oil and gas downhole environments. A single fiber optic cable temporarily or permanently installed in the well provides the distributed measurement along the wellbore. There are no electrical wires, no sensors, no electrical connections, or electronics along the line. It requires no installation of downhole equipment and does not intervene in the operations. The system can be used when it is necessary to obtain distributed measurements from wellbores in real-time. Therefore applications of fiber optic sensing technology are not limited to the above. Full-length wellbore characteristics can also be transferred to the surface in real-time using this system. įiber optics do not only provide continuous monitoring.Some well completion operations where fiber optic sensing can be applied are listed as below: In the last decade, distributed sensing technology was applied to various areas in the oil and gas industry with special interest in well completion operations.