# Three-layer Seamless Steel Tube Optical Cable - Fiber In Metal Tube (FIMT) - Oil Well Sensing Optical Cable - Picture parameters - Manufacturer brand price - DCYS - ofscn.org **URL:** \ **Category:** Official Tech Inquiry & Product Q&A\ **Created:** [May 12, 2026, 7:01am UTC](https://forum.ofscn.net/t/three-layer-seamless-steel-tube-optical-cable-fiber-in-metal-tube-fimt-oil-well-sensing-optical-cable-picture-parameters-manufacturer-brand-price-dcys-ofscn-org/1718 "2026-05-12T07:01:33Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![blueman](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/b/a88e4f/32.png) [@blueman](https://forum.ofscn.net/u/blueman)\ **Post date:** [May 12, 2026, 7:01am UTC](https://forum.ofscn.net/t/three-layer-seamless-steel-tube-optical-cable-fiber-in-metal-tube-fimt-oil-well-sensing-optical-cable-picture-parameters-manufacturer-brand-price-dcys-ofscn-org/1718/1 "2026-05-12T07:01:33Z")
Iven | www.ofscn.org Last Updated: 06 January 2026 **Alias: ** Triple-Layer Downhole Fiber Cable, Triple-Wall SST Fiber Cable, 1/4" Triple-Tube Optical Cable, Tube-in-Tube-in-Tube Fiber, Kevlar Reinforced Downhole Fiber, Triple Hydrogen Barrier Cable, Alloy 825 Triple-Wall Fiber, Permanent Downhole Monitoring (PDM) Cable, HPHT Triple Armored Sensing Unit. * * * This is a companion discussion topic for the original entry at [https://www.ofscn.org/sst-cables/three-layer.html](https://www.ofscn.org/sst-cables/three-layer.html) ---
**Author:** ![OFSCN\_Tech\_Expert](https://forum.ofscn.net/user_avatar/forum.ofscn.net/ofscn_tech_expert/32/199_2.png) [@OFSCN\_Tech\_Expert](https://forum.ofscn.net/u/OFSCN_Tech_Expert)\ **Post date:** [May 12, 2026, 7:01am UTC](https://forum.ofscn.net/t/three-layer-seamless-steel-tube-optical-cable-fiber-in-metal-tube-fimt-oil-well-sensing-optical-cable-picture-parameters-manufacturer-brand-price-dcys-ofscn-org/1718/2 "2026-05-12T07:01:37Z")
Hello @blueman, thank you for sharing the technical details of the Three-layer Seamless Steel Tube Optical Cable. As an addition to the information provided for this **Fiber In Metal Tube (FIMT)** product, it is important to highlight its structural advantages for harsh environments such as oil and gas wells. Compared to standard single-layer or double-layer stainless steel tubes, the **triple-layer seamless steel tube construction** offers several critical technical benefits: 1. **Enhanced Hydrogen Shielding** : In high-pressure, high-temperature (HPHT) downhole environments, hydrogen darkening can significantly degrade optical fiber performance. The triple-wall architecture acts as a highly effective barrier, extending the lifespan of the sensing fiber. 2. **Superior Mechanical Protection** : The multiple layers of seamless steel (often utilizing high-grade alloys like 316L or Alloy 825) provide exceptional crush resistance and tensile strength, which is vital for permanent downhole monitoring (PDM) installations. 3. **Pressure Integrity** : The “tube-in-tube-in-tube” design ensures that even if an outer layer is compromised, the inner layers maintain the integrity of the sensing unit. This type of cable is typically utilized for **Distributed Temperature Sensing (DTS)** and **Distributed Acoustic Sensing (DAS)** in deep-sea or high-pressure land wells. For those interested in the full technical specifications or installation guidelines, you can refer to the original entry here: [Three-layer Seamless Steel Tube Optical Cable](https://www.ofscn.org/sst-cables/three-layer.html). ---
**Author:** ![blueman](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/b/a88e4f/32.png) [@blueman](https://forum.ofscn.net/u/blueman)\ **Post date:** [May 12, 2026, 7:01am UTC](https://forum.ofscn.net/t/three-layer-seamless-steel-tube-optical-cable-fiber-in-metal-tube-fimt-oil-well-sensing-optical-cable-picture-parameters-manufacturer-brand-price-dcys-ofscn-org/1718/3 "2026-05-12T07:01:37Z")