Low-voltage fiber optic cables, including hybrid optical-power cables, enable both communication and power delivery in wells, supporting monitoring and data acquisition in challenging downhole environments.

Overview

Fiber optic cables in low-voltage well applications are designed to transmit data while often carrying minimal electrical power for sensors or monitoring equipment. These cables are used for distributed sensing, temperature, strain, and microseismic monitoring in oil and gas wells, as well as in industrial and utility applications . They can be deployed in both new and existing wells, and some designs are disposable for cost-effective, temporary monitoring .

Types of Low-Voltage Fiber Optic Cables

1. Hybrid Optical-Power Cables (OPLC)
   • Combine optical fibers and copper conductors in a single cable, allowing simultaneous data transmission and low-voltage power delivery .
   • Suitable for fiber-to-the-home (FTTH), intelligent power grids, and well monitoring systems.
   • Reduce installation costs by eliminating the need for separate power and communication lines.
   • Designed for mechanical durability, including impact and pressure resistance, and can operate in harsh environments .
2. Disposable Fiber Optic Cables
   • Single-use fibers like ExpressFiber™ can be pumped downhole in wells to monitor cross-well interactions, fracture growth, and microseismic events .
   • These fibers are bare (without protective layers), making them sensitive but cost-effective for temporary monitoring.
   • Can be deployed in extended-reach wells up to 30,000 feet and withstand downhole conditions for the duration of stimulation operations .
3. Subsea Low-Voltage Fiber Optic Cables
   • Designed for integration into umbilicals with hydraulic tubes or high-voltage cables.
   • Use loose tube designs with fibers protected by stainless steel tubes filled with water-blocking compounds to prevent signal loss and intrusion .
   • Suitable for offshore wells, wind farms, and subsea power grids.

Key Features

• Data Transmission: Supports high-bandwidth communication for monitoring sensors and distributed acoustic sensing (DAS).
• Power Delivery: Provides low-voltage power to downhole instruments or sensors.
• Durability: Resistant to pressure, temperature, and mechanical stress in well environments.
• Cost Efficiency: Hybrid and disposable designs reduce installation and operational costs .
• Flexibility: Can be used in both permanent and temporary monitoring setups, including existing wells.

Applications

• Oil and Gas Wells: Monitoring fracture propagation, well interference, and microseismic activity.
• Industrial and Utility Systems: Power and data integration for smart grids, FTTH, and remote sensing.
• Subsea Installations: Reliable communication and low-voltage power delivery in underwater environments . Low-voltage fiber optic cables provide a versatile solution for simultaneous data and power transmission, enabling real-time monitoring and operational efficiency in wells and other challenging environments. Their hybrid and disposable designs make them adaptable for both permanent installations and temporary monitoring projects .