Silicone Coating Prevents Fiber Adhesion in High-Temp Wellbores
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fiber optic cables used in high temperature downhole oil and gas well applications face issues with fiber adhesion due to thermal expansion, leading to increased optical loss after temperature reduction, as coatings become brittle and fibers fail to return to their original orientation.
Innovation Solution
The use of highly-cured polyimide coatings and high temperature rated substances applied to fibers to prevent adhesion during thermal recovery operations, ensuring the fibers maintain their orientation and reduce optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If excess fiber length is introduced to avoid tension on fibers at high temperatures, then fiber tension is reduced, but fiber adhesion occurs during thermal recovery operations
Solution Approach 1:
A silicone-based substance is applied as an intermediary coating between the fiber and the cable structure. This substance acts as a mediator that prevents direct adhesion between the fiber and cable components while allowing the fiber to maintain its sinusoidal orientation and avoid tension during high-temperature operations.
Solution Approach 2:
The patent changes the physical and chemical parameters of the coating material by using a silicone-based substance instead of traditional polyimide coatings. This substance maintains flexibility at high temperatures and does not undergo the same adhesion issues, allowing the fiber to return to its original orientation after thermal recovery.
2Strength
If polyimide coatings are used on fibers for high temperature operations, then fiber protection is provided, but coating brittleness occurs at temperatures above 300 degrees Celsius
Solution Approach 1:
The patent changes the material composition parameter by replacing polyimide with a silicone-based coating substance. This new material maintains its flexibility and protective properties at temperatures above 300 degrees Celsius, avoiding the brittleness issue that plagues traditional polyimide coatings.
Solution Approach 2:
The patent employs a composite structure where the silicone-based substance is applied over the existing fiber coating system. This composite approach combines the protective function of the original coating with the high-temperature flexibility of the silicone-based material.
3Stability of the object's composition
If fibers are allowed to adhere to cable inner wall during thermal recovery, then cable structure stability is maintained, but optical loss increases due to tight bends
Solution Approach 1:
The silicone-based substance serves as a non-adhering intermediary layer between the fiber and the cable inner wall. This allows the cable structure to maintain stability during thermal recovery while preventing the fiber from adhering to the wall, thereby avoiding tight bends and optical loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents fiber adhesion during high temperature operations, maintaining optimal fiber alignment and reducing optical loss, thus enhancing the reliability and performance of fiber optic cables in extreme environments.
Implementation Method 1
the fibers do not adhere to each other or to an inner wall of the cable during a high temperature operation
Implementation Method 2
coatings may adhere at contact points with each other or to an inner wall of the cable either through partial melting or chemical bonding of the coatings
Implementation Method 3
introducing excess fiber length (EFL) to avoid tension on the one or more fibers 114 at high temperatures due to thermal expansion of the cable components
Implementation Method 4
At 350 degrees Celsius, the coating on the fibers may become brittle. After a thermal recovery operation, which may last over 30 days, when the cable temperature may then be reduced, the cable structure contracts and the fibers 114 within the cable 110 may return to a state of increased EFL
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
Embodiments of the present invention provide methods and apparatus for cables having one or more fibers that may function as a sensing device within a wellbore, wherein the fibers do not adhere to each other or to an inner wall of the cable during a high temperature operation, such as in a thermal recovery operation that may last over 30 days.