Optical fiber for distributed temperature sensing (DTS) OFS Specialty Photonics Division
GeoSil™ Fibers

GeoSil™ Pure Silica Core Optical Fibers are now available in single-mode or multimode designs for Distributed Temperature Sensing (DTS) and other geophysical well applications. The pure core design is critical to the performance of optical fibers deployed down oil or gas wells where conditions include temperatures that routinely exceed 250°C with high pressure and hydrogen gas. GeoSil fibers are coated with PYROCOAT® polyimide, a specialty coating that allows temperature performance to 300°C and imparts abrasion and chemical resistance plus a small form factor (155 µm diameter) to the sensing fiber in a DTS system. When conventional fibers with germanium-doped cores are exposed to hydrogen at high temperatures, permanent defects can occur. These defects can result in a rise in attenuation which significantly limits the lifetime of the fiber sensor. Optical fiber with a pure silica core is extremely resistant to this phenomenon and can perform far longer in the downhole environment limiting the expense associated with replacement of new sensors. These fibers are part of the GeoFibers™ family of products optimized for geophysical applications.

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