Isolated Sensor Housing With Hydrogen Barrier Coating
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Solution Overview
Problem
Conventional optical sensors with germanium-doped silica fibers are not sufficiently stable for prolonged use in harsh oil and gas well environments due to increased attenuation losses from hydrogen diffusion, and existing isolated sensors are too large for tight spaces.
Innovation Solution
A flexible sensor tube with a porous, permeable element and a clean transmission fluid within a sealed housing, allowing pressure and temperature measurements without direct exposure to harsh conditions, using a smaller diameter design that can be deployed in tighter spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional germanium-doped silica fibers are used in harsh oil well environments, then the sensor can be deployed, but attenuation losses increase due to hydrogen diffusion causing instability
Solution Approach 1:
The patent introduces a hydrogen barrier coating as an intermediary layer between the optical fiber and the harsh well environment. This coating acts as a mediator that prevents hydrogen diffusion into the fiber while allowing the fiber to remain exposed to temperature and pressure conditions for sensing.
Solution Approach 2:
The patent extracts the hydrogen barrier function from the fiber coating structure by applying a separate, dedicated hydrogen barrier coating layer. This separates the hydrogen protection function from the mechanical protection function, allowing each to be optimized independently.
2Reliability
If optical sensors are isolated from harsh environments using conventional housing, then measurement stability improves, but the housing diameter becomes too large for tight spaces
Solution Approach 1:
The patent extracts the isolation function from a separate housing structure and integrates it directly into the sensor assembly itself. The sensor is designed to be self-contained with the hydrogen barrier coating providing environmental protection without requiring an external housing.
Solution Approach 2:
The patent merges the environmental protection function with the sensor structure by integrating the hydrogen barrier coating directly onto the optical fiber. This combines multiple functions (sensing, protection, and isolation) into a single integrated assembly, eliminating the need for separate housing.
3Loss of energy
If carbon coating is applied to reduce hydrogen diffusion, then attenuation losses decrease at lower temperatures, but effectiveness diminishes rapidly as temperature increases
Solution Approach 1:
The patent uses a composite coating structure consisting of multiple layers with different properties. The hydrogen barrier coating is applied over the conventional carbon coating, creating a composite structure where each layer contributes different protective functions that remain effective across a wide temperature range.
Solution Approach 2:
The patent changes the material parameters of the coating by selecting materials with appropriate glass transition temperatures and hydrogen barrier properties. The hydrogen barrier coating is specifically chosen to maintain its barrier effectiveness at high temperatures where conventional carbon coatings fail.
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
The solution provides stable and accurate pressure and temperature measurements in harsh environments while minimizing the sensor size, enabling deployment in tight spaces and reducing hydrogen diffusion effects.
Implementation Method 1
pressure is communicated to the flexible sensor tube so that the pressure is transferred by the transmission fluid to the optical sensor
Implementation Method 2
The flexible sensor tube can be at least partially covered by a porous, permeable element
Data Source
AI summary
Disclosed is a sensor housing having a flexible sensor tube containing a transmission fluid and having sealed ends, and an optical sensor connected to an optical fiber. The optical sensor is adapted to measure a pressure of a fluid and this pressure is communicated to the flexible sensor tube, so that the pressure is transferred by the transmission fluid to the optical sensor. The sensor can measure temperature and/or pressure, and the sensor can be located remote from the sensor housing or within the sensor housing.