FDR Wellbore Fluid Level Measurement Without Conductors
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Solution Overview
Problem
Existing methods for measuring fluid levels in oil, gas, and water wells suffer from limited accuracy, resolution, and reliability, particularly in uncased boreholes or when casing conductivity is compromised, and rely on costly and time-consuming signal conductors.
Innovation Solution
A method utilizing Frequency Domain Reflectometry (FDR) to transmit and receive electromagnetic signals through the well's bore and annulus, determining fluid levels and characteristics by analyzing time differences in signal reflections, without relying on conductive paths or signal conductors, and using FDR sensors positioned at the wellhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic signals are transmitted along an electrically conductive coaxial path through tubing and casing, then fluid level measurements can be obtained, but the method provides limited accuracy and resolution and becomes unreliable when casing conductivity is compromised or tubing contacts casing
Solution Approach 1:
The patent replaces the mechanical/electrical coaxial cable transmission system with an electromagnetic wave propagation system through the wellbore fluids and formation. Instead of using conductive tubing and casing as signal paths, the system transmits electromagnetic signals directly through the fluid columns and uses the dielectric properties of the fluids to enable measurement, eliminating the reliability issues associated with conductor integrity
Solution Approach 2:
The invention changes the measurement parameter from electrical conductivity-based measurements to dielectric constant-based measurements. By measuring the dielectric properties of the fluids in the wellbore, the system achieves more accurate and reliable fluid level detection that is not affected by casing conductivity or tubing-casing contact
2Measurement precision
If signal conductors are installed to convey electromagnetic signals downhole, then measurements can be obtained, but the installation becomes costly and time-consuming
Solution Approach 1:
The patent extracts and eliminates the signal conductor component from the measurement system. By using the wellbore fluids and formation itself as the transmission medium for electromagnetic signals, the system removes the need for separate conductor installation, thereby reducing both cost and installation time while maintaining measurement capability
Solution Approach 2:
The invention makes the wellbore fluids serve multiple functions: they act as both the target of measurement and as the transmission medium for electromagnetic signals. This multi-functionality eliminates the need for dedicated signal conductors, simplifying the system and reducing installation complexity
3Adaptability or versatility
If electromagnetic signals are transmitted through uncased boreholes or when casing conductivity is compromised, then coverage is improved, but existing methods provide unreliable or inaccurate measurements
Solution Approach 1:
The patent replaces the electrical conductor-based system with an electromagnetic wave-based system that propagates through dielectric media. This substitution enables the system to function in uncased boreholes and compromised casing conditions because electromagnetic waves can travel through air and various materials without requiring continuous electrical conductivity
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
Provides enhanced sensitivity, range, accuracy, and resolution in measuring fluid levels and characteristics, enabling real-time monitoring and control of fluid production or injection, and reducing installation costs by eliminating the need for signal conductors.
Implementation Method 1
A method utilizing Frequency Domain Reflectometry (FDR) to transmit and receive electromagnetic signals through the well's bore and annulus, determining fluid levels and characteristics by analyzing time differences in signal reflections
Data Source
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AI summary
There is disclosed in one implementation a method of or for use in or for detecting, measuring and/or determining at least one variable or characteristic in a space, such as a well, container or vessel. In one implementation the method comprises: transmitting a first electromagnetic signal from a first position to a feature within the space; receiving a second electromagnetic signal at a second position after reflection of the transmitted first electromagnetic signal from the feature; transmitting a third electromagnetic signal from a third position to a calibration feature within the space; receiving a fourth electromagnetic signal at a fourth position after reflection of the transmitted third electromagnetic signal from the calibration feature. The method further comprises: subsequently transmitting a further first electromagnetic signal from the first portion to the feature; receiving a further second electromagnetic signal at the second position after reflection of the transmitted further first electromagnetic signal from the feature; transmitting a further third electromagnetic signal from the third position to the calibration feature; receiving a further fourth electromagnetic signal at the fourth position after reflection of the transmitted further third electromagnetic signal from the calibration feature. In so doing one can determining (the) at least one variable or characteristics from a difference or variation in time between the transmission of the first electromagnetic signal and reception of the second electromagnetic signal and the transmission of the further first electromagnetic signal and receipt of the further second electromagnetic signal and a difference or variation in time between the transmission of the third electromagnetic signal and receipt of the fourth electromagnetic signal and the transmission of the further third electromagnetic signal and receipt of the further fourth electromagnetic signal.