Optical Fiber Flow Meter for Geothermal Boreholes
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Solution Overview
Problem
Measuring fluid flow velocity and volume in boreholes and pipelines is challenging due to inaccessible locations, dirty or reactive fluids, and extreme temperature conditions, making existing methods inefficient for geothermal heat reservoir investigations.
Innovation Solution
A method and sensing device that measure fluid temperature using a heated sensing device with a first sensor element and a second temperature-sensitive element, allowing for the calculation of fluid velocity, and optionally using Distributed Temperature Sensing (DTS) or Fiber Bragg Grating technology to extend measurements over long distances and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional thermal flow meters with discrete temperature sensors are used, then the measurement is simple and device complexity is low, but the measurement coverage is limited and cannot measure flow over long distances
Solution Approach 1:
The patent replaces traditional mechanical/discrete temperature sensors with optical fiber sensing technology. The optical fiber acts as a continuous distributed sensor that can measure temperature along its entire length, enabling flow measurement over long distances without increasing mechanical device complexity. The optical fiber senses temperature changes caused by fluid flow and transmits this information optically to the measurement system.
Solution Approach 2:
The patent transitions from point-based temperature measurement (discrete sensors at specific locations) to distributed continuous measurement along the entire optical fiber length. This dimensional change from 0D point measurements to 1D distributed measurements enables coverage over long distances while maintaining a relatively simple device structure.
2Reliability
If discrete temperature sensors are used in inaccessible locations, then the device structure is simple, but measurement accessibility and reliability in harsh environments deteriorate
Solution Approach 1:
The patent replaces traditional electrical temperature sensors with optical fiber sensors that can be deployed in inaccessible and harsh environments. Optical fibers are immune to electromagnetic interference, corrosion, and can withstand extreme temperatures, significantly improving measurement reliability in geothermal and industrial applications while maintaining ease of installation through their flexible, cable-based structure.
Solution Approach 2:
The optical fiber sensor operates in an electrically inert and chemically resistant manner, unaffected by electromagnetic fields, corrosive fluids, or extreme temperatures. This inert operation mode allows reliable measurement in harsh environments where traditional electrical sensors would fail or require complex protection.
3Adaptability or versatility
If conventional flow measurement methods are used in geothermal reservoirs, then the equipment requirements are standard, but the ability to measure in extreme temperature conditions and remote locations deteriorates
Solution Approach 1:
The patent replaces conventional electrical sensing systems with optical fiber-based temperature sensing. Optical fibers can operate in extreme temperature ranges found in geothermal reservoirs, provide distributed measurement along the fiber length, and can be deployed in remote locations through wellbores or pipelines, significantly enhancing adaptability without requiring complex specialized equipment.
Solution Approach 2:
The optical fiber sensor serves multiple functions: it acts as both the sensing element and the signal transmission medium, can be deployed in various configurations (distributed along pipelines, coiled in boreholes), and provides continuous temperature profile data that can be used for multiple measurement purposes, enhancing versatility across different geothermal applications.
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
Enables precise measurement of fluid velocity and volume flow in spatially extensive areas, including boreholes and pipelines, with improved accuracy and applicability to demanding environments like geothermal heat reservoirs.
Implementation Method 1
heating the sensing device with a first sensor element of the sensing device
Implementation Method 2
measuring a temperature of the sensing device with a second sensor element being different from the first sensor element
Implementation Method 3
The convective heat transfer behavior of cylinders, which are transversely arranged in a fluid flow, has been investigated theoretically and experimentally
Data Source
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AI summary
A method for measuring a fluid flow using a heated sensing device arranged in the fluid flow comprises the steps of measuring a temperature of the fluid, heating the sensing device with a first sensor element of the sensing device, measuring a temperature of the sensing device with a second sensor element being different from the first sensor element, and calculating a fluid velocity using the difference between the measured temperature of the sensing device and the measured temperature of the fluid. This measuring method enables measuring flow velocity and volume flow in boreholes, pipelines or other demanding places.