Optical fiber cables used for logging in Denmark include high-performance downhole cables for well monitoring and submarine cables like COBRA for data transmission, designed for high reliability under extreme conditions.

Downhole Optical Fiber Logging Cables

Optical fiber logging cables are used in oil and gas wells to measure geophysical parameters such as temperature, strain, and acoustic signals. Unlike traditional electrical logging cables, optical fiber sensors are resistant to electromagnetic interference and can operate under high temperature, high pressure, and corrosive environments . These cables often use a fiber-in-metal-tube (FIMT) design, where optical fibers are hermetically sealed in stainless steel or INCONEL tubes, sometimes filled with protective gels to prevent microbending and chemical ingress . The FIMT is supported by an extruded polymer layer and an outer tube that provides mechanical shielding and pressure resistance. Cables can be customized for fiber type, quantity, armor, and encapsulation, and are prestressed during manufacturing to minimize strain and optical degradation .

Cable Injection and Deployment

For well logging, optical fiber cables can be deployed using cable injection or coiled tubing methods. Cable injection allows the optical fiber to be inserted into the wellbore while maintaining signal integrity, whereas coiled tubing can push the cable to the target depth for conventional logging operations . Optical fiber logging provides distributed measurement capability, enabling spatial profiling of wellbore conditions with high precision.

Fiber Optic Cables in Denmark

In Denmark, fiber optic cables are also used for high-speed data transmission. For example, the COBRA submarine cable connects the Netherlands and Denmark, providing a reliable, high-bandwidth route for international data traffic . These cables are typically available in single-mode and multimode configurations, designed to minimize signal loss over long distances and withstand harsh environmental conditions . Local suppliers like Farnell Denmark and Scankab offer a range of fiber optic cables suitable for telecommunications, data centers, and industrial applications .

Summary

• Downhole logging cables: Fiber-in-metal-tube design, high temperature and pressure resistance, distributed sensing, prestressed for reliability .
• Deployment methods: Cable injection, coiled tubing, or pipe transportation for vertical and inclined wells .
• Submarine and terrestrial cables in Denmark: COBRA cable for international connectivity, single-mode and multimode fibers, high-speed data transmission, robust environmental protection .
• Advantages over electrical cables: Immunity to electromagnetic interference, small cross-sectional area, high precision, and durability in extreme conditions . These specifications ensure that optical fiber cables used in Denmark, whether for logging or data transmission, provide reliable, high-performance operation in demanding environments.