Downhole Detection via Electromagnetic Wave Propagation
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Solution Overview
Problem
Current methods for measuring fluid levels in oil, gas, and water wells, such as electromagnetic pulse techniques, suffer from limited accuracy and resolution, and are unreliable in uncased boreholes or when there are breaks in casing conductivity, necessitating the development of a more sensitive and reliable method for distance measurement.
Innovation Solution
A method involving the transmission and reception of electromagnetic signals from the surface to a downhole feature in a well, using a system that does not rely on signal conductors or coaxial paths, allowing for enhanced distance measurement sensitivity, range, and accuracy by determining the distance between the surface and the downhole feature through the analysis of reflected signals, utilizing frequencies between 1 GHz to 100 GHz and employing Frequency Domain Reflectometry (FDR) techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic pulse techniques are used for fluid level measurement, then the measurement can be performed, but the accuracy and resolution are limited
Solution Approach 1:
The patent replaces traditional mechanical/conductive signal transmission systems with electromagnetic wave propagation through the borehole annulus. The system uses electromagnetic waves transmitted from surface equipment through the space between the borehole casing and formation, eliminating the need for conductive tubing or packers to transmit signals downhole. This substitution enables accurate measurements in uncased boreholes and situations where conventional conductive paths are compromised.
Solution Approach 2:
The patent employs Frequency Domain Reflectometry (FDR) techniques, transmitting electromagnetic signals across a broad frequency spectrum (1 GHz to 100 GHz) and analyzing the reflected signals to determine fluid level positions. By changing the frequency parameters and analyzing the spectral characteristics of reflected waves, the system achieves enhanced measurement precision and resolution compared to traditional single-frequency electromagnetic pulse methods.
2Reliability
If conventional electromagnetic signal transmission through conductive paths is used, then signals can be transmitted, but the system becomes unreliable when casing conductivity is broken
Solution Approach 1:
The patent eliminates the requirement for continuous electrically conductive paths by using electromagnetic wave propagation through the borehole annulus. The electromagnetic signals are transmitted from surface equipment through the space between the borehole casing and formation, allowing signal transmission without relying on the conductivity of tubing, packers, or casing. This fundamentally changes how signals are transmitted downhole, making the system reliable even when conductive paths are broken.
Solution Approach 2:
The system provides universal applicability across different well configurations including cased and uncased boreholes, production wells, injection wells, and situations with broken casing conductivity. The electromagnetic wave propagation method through the borehole annulus serves multiple functions: fluid level measurement, and can be applied regardless of the well's operational status or structural configuration, eliminating the need for separate systems for different well types.
3Measurement precision
If traditional distance measurement methods are used, then measurements can be obtained, but the sensitivity and range are limited
Solution Approach 1:
The patent employs Frequency Domain Reflectometry (FDR) techniques, transmitting electromagnetic signals across a broad frequency spectrum (1 GHz to 100 GHz) and analyzing the reflected signals to determine fluid level positions. By changing the frequency parameters and analyzing the spectral characteristics of reflected waves, the system achieves enhanced measurement precision and resolution compared to traditional single-frequency electromagnetic pulse methods.
Solution Approach 2:
The system transmits electromagnetic signals periodically across a range of frequencies and analyzes the reflected signals to determine distance. The periodic variation in frequency and the analysis of reflected signal characteristics enables the system to achieve both high sensitivity for small distance measurements and extended range capability, overcoming the limitations of traditional methods.
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
This approach provides real-time, accurate, and sensitive measurements of fluid levels and interfaces, enabling effective control of fluid production and injection, and is applicable to both production and injection wells, including those with complex geometries and obstructions, without the need for invasive conductors.
Implementation Method 1
transmitting an electromagnetic signal from a first position located substantially at or adjacent to surface through a first space to the downhole feature
Implementation Method 2
receiving an electromagnetic signal at a second position located substantially at or adjacent to surface after reflection of the transmitted electromagnetic signal from the downhole feature
Data Source
AI summary
A method for use in or for detecting a downhole feature in a well comprises transmitting an electromagnetic signal from a first position located substantially at or adjacent to surface through a first space to the downhole feature. The method further comprises receiving an electromagnetic signal at a second position located substantially at or adjacent to surface after reflection of the transmitted electromagnetic signal from the downhole feature and after propagation of the reflected electromagnetic signal through a second space. The method may comprise sealing the well before transmitting the electromagnetic signal. Such a method may be used to detector determine a distance from surface to a downhole feature such as a fluid interface in a completed production, injection or observation well.