High Temperature Fiber Optic Cable Metal Construction
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Solution Overview
Problem
Conventional fiber optic cables face issues in high temperature environments, such as oil and gas wells, due to hydrogen evolution from plastic compounds, limited temperature range, and fatigue of metallic tubing in slickline cables, which affects deployment, buckling strength, and service life.
Innovation Solution
A fiber optic cable design featuring an outer metal tube with multiple inner metal elements, including optical fibers and metallic fillers, constructed from high-temperature-resistant materials like stainless steel, allowing direct deployment and enhanced mechanical robustness for high-temperature, zero fiber strain, and increased fatigue resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic compounds (ETFE/Teflon) are used in cable construction, then ease of manufacture and processing are improved, but hydrogen evolution occurs at elevated temperatures which deteriorates optical performance
Solution Approach 1:
The patent removes plastic compounds (ETFE/Teflon) from the cable construction entirely and replaces them with metal tubing and metallic fillers. This extraction eliminates the source of hydrogen evolution that degrades optical performance, while maintaining cable structural integrity through alternative materials designed for high-temperature stability.
Solution Approach 2:
The patent employs a composite construction using metal tubing, metallic fillers, and fiber optic elements. This composite structure replaces the problematic plastic-based materials with a combination of metal components that provide both mechanical strength and thermal stability, preventing hydrogen evolution while preserving optical fiber performance at elevated temperatures.
2Temperature
If conventional polymers are used to increase temperature resistance, then temperature capability is improved up to 300 degrees C., but the upper temperature limit remains insufficient for 600 degrees C or higher applications
Solution Approach 1:
The patent fundamentally changes the material parameter from polymer-based to metal-based construction. By transitioning from organic polymers (which decompose at high temperatures) to inorganic metal materials with high melting points and thermal stability, the cable achieves reliable operation at 600 degrees C and above, far exceeding the limitations of conventional high-temperature polymers.
3Strength
If metallic tubing is used in slickline cables for direct deployment, then buckling strength and mechanical robustness are improved, but fatigue and fracture occur after certain number of cycles reducing service life
Solution Approach 1:
The patent creates a composite cable structure where metal tubing provides external mechanical strength and buckling resistance, while internal fiber optic elements and metallic fillers contribute to overall structural integrity. This composite design distributes mechanical stresses across multiple components, reducing fatigue accumulation in any single element and extending service life compared to solid metallic slickline cables.
Solution Approach 2:
The cable is segmented into multiple functional elements: outer metal tubing for mechanical strength, inner metal tubing for fiber protection, and metallic fillers for structural support. This segmentation allows each component to specialize in specific functions, with the fiber optic elements being inherently fatigue-resistant compared to solid metal, thereby extending overall cable durability.
4Reliability
If heat treatment is applied to metal tubing to enhance fatigue life, then fatigue resistance is improved, but the temperature exceeds the rating of fiber optic or copper core
Solution Approach 1:
The patent eliminates the need for heat treatment by removing the fiber optic or copper core from the structure that requires fatigue enhancement. By using all-metallic construction with fatigue-resistant metal alloys and designs, the cable achieves enhanced fatigue life without subjecting temperature-sensitive optical or electrical cores to damaging heat treatment temperatures.
Data Source
AI summary
A cable including an outer metal tube and a first layer wire inside the outer metal tube, wherein the first layer wire has five inner elements surrounding a metallic center member and at least one of the inner elements is a metal tube containing an optical fiber.