Downhole Powerhouse: How OFSCN® Carbon-Sealed PI Fiber Resists High Pressure, High Temperature, and Hydrogen Darkening

 

Company Name	Beijing Dacheng Yongsheng Technology Co., Ltd. (DCYS)
Product Brand	OFSCN®
Product Model	300℃ SM Polyimide Optical Fiber (Maximum Operating Temperature 350℃)

Introduction: The Three "Invisible Killers" of the Downhole Environment

In downhole sensing applications such as oil, gas, and geothermal energy, the optical fiber acts as the "nervous system" for data retrieval. However, the downhole environment is widely recognized as one of the most demanding, where the fiber must withstand three "invisible killers": sustained high temperature, immense pressure, and hydrogen ingress (hydrogen darkening). Insufficient protection against any one of these can lead to the complete failure of expensive downhole monitoring systems.

The OFSCN® Carbon-Sealed Polyimide (PI) Optical Fiber is a high-reliability specialty fiber specifically engineered to conquer these extreme challenges.

I. The Ultimate Solution to the High-Temperature Challenge: The PI Coating

Traditional acrylate fibers rapidly age when temperatures exceed +125℃, leading to signal distortion or even interruption. For deep well environments that often reach 200℃ or even 300℃, the PI coating is the only viable choice.

• Temperature Limit Breakthrough: The OFSCN® PI fiber can operate stably at sustained high temperatures of up to +350℃, far exceeding industry standards. Its polyimide coating has an extremely high thermal decomposition temperature, preventing carbonization or cracking even under high heat, thereby ensuring the long-term reliability of the fiber during high-temperature operations.
• Wide Temperature Range Stability: The fiber also possesses excellent resistance to ultra-low temperatures (down to -200℃), making it suitable for complex thermal gradient environments, from the frigid surface to the scorching well bottom.

II. The "Impervious Steel Garment" Against Hydrogen Darkening: Carbon Sealing Technology

In downhole environments, high temperatures accelerate the penetration of hydrogen molecules into the fiber core, leading to hydrogen darkening (i.e., a permanent increase in fiber attenuation). This is one of the most common causes of downhole cable failure.

OFSCN® utilizes a unique Carbon Sealing value-added option, which completely resolves this issue:

1. Barrier Isolation: A dense carbon sealing layer is deposited between the fiber's cladding and the Polyimide coating. This carbon film acts as an impenetrable physical barrier.
2. Molecular Isolation: It effectively prevents the diffusion and penetration of highly permeable hydrogen molecules H₂ toward the fiber core at high temperatures.
3. Longevity Assurance: By eradicating hydrogen darkening, the Carbon-Sealed PI fiber greatly extends the service life of the fiber in hydrogen-containing, high-pressure, high-temperature oil and gas environments, securing the long-term accuracy of sensing data.

III. Mechanical Assurance Against High Pressure and High Stress

The deployment of downhole cables involves immense tensile stress, and the working formation pressure poses a fatal threat to the fiber. The OFSCN® Carbon-Sealed PI fiber provides dual mechanical assurance:

• Ultra-High Tensile Strength: The fiber boasts a tensile strength of up to 100 kpsi (kilo-pounds per square inch), ensuring the fiber's mechanical integrity is not compromised during the tight tubing of cable manufacturing (such as FIMT) or under the significant tension forces during downhole deployment.
• Stress Resistance: The superior properties of the Polyimide coating help the fiber resist lateral pressure and micro-bending loss, ensuring stable optical performance even when compressed within metal tubes or sensing cable assemblies.

Conclusion: The Reliable Foundation for Downhole Sensing

The OFSCN® Carbon-Sealed Polyimide Optical Fiber forms a robust protection system against the three major downhole threats through the PI coating's high-temperature resistance, the carbon seal layer's anti-hydrogen darkening capability, and the 100kpsi high mechanical strength. It is the ideal core component for achieving long-term, reliable operation of high-precision downhole sensing systems, such as Distributed Temperature Sensing (DTS) and Fiber Bragg Gratings (FBG).

Company Name	Beijing Dacheng Yongsheng Technology Co., Ltd. (DCYS)
Product Brand	OFSCN®
Product Model	300℃ SM Polyimide Optical Fiber (Maximum Operating Temperature 350℃)
Product Details Page	https://www.ofscn.org/optical-fibers/polyimide-coated-sm-300.html

Contact us immediately to safeguard your critical energy assets with this downhole powerhouse!

All data in this document are typical values. Specific specifications an