NMR Tool Antenna Radial Projections Eddy Current Noise Reduction
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Solution Overview
Problem
Nuclear magnetic resonance (NMR) tools used in well drilling operations face reduced accuracy due to noise introduced by eddy currents generated in conductive media, which limits the signal-to-noise ratio (SNR) of magnetic resonance response measurements.
Innovation Solution
Incorporating tilted, radial projections made of non-conductive materials around the antenna of the NMR tool disrupts eddy currents, allowing for improved fluid flow and reducing the strength of secondary electromagnetic fields, thereby enhancing the SNR of magnetic resonance response measurements without displacing conductive media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If antennas are used to generate eddy currents in conductive media for NMR measurements, then magnetic resonance response can be obtained, but noise is introduced that reduces measurement accuracy and signal-to-noise ratio
Solution Approach 1:
The patent extracts and removes the harmful eddy currents from the measurement system by introducing non-conductive projections that disrupt the conductive pathways. These projections physically interrupt the eddy current loops, separating the harmful electromagnetic noise from the useful magnetic resonance signal, thereby improving measurement accuracy without eliminating the antenna's measurement function
Solution Approach 2:
The non-conductive projections serve as intermediary elements between the antenna and the conductive media. These projections mediate the interaction by disrupting eddy current formation while allowing the magnetic field to penetrate and induce magnetic resonance in the formation, thus protecting the measurement system from noise while maintaining measurement capability
2Measurement precision
If non-conductive projections are added to disrupt eddy currents, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the tool body into modular sections with discrete non-conductive projections attached at specific locations. Rather than redesigning the entire tool structure, the solution segments the problem into individual projection elements that can be independently positioned and optimized, simplifying the overall design while achieving SNR improvement
Solution Approach 2:
The non-conductive projections are strategically placed only in specific locations where eddy currents are most problematic, rather than covering the entire tool. This local quality approach applies the complexity-enhancing feature only where needed to disrupt harmful current patterns, minimizing overall device complexity while maximizing measurement precision in critical areas
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 effectively increases the signal-to-noise ratio of magnetic resonance response measurements, improving the accuracy and efficiency of NMR tools by minimizing noise from eddy currents while maintaining fluid flow past the tool.
Implementation Method 1
These antennas may generate eddy currents in conductive media surrounding the tool that introduce noise into the measurements
Implementation Method 2
Incorporating tilted, radial projections made of non-conductive materials around the antenna of the NMR tool disrupts eddy currents, allowing for improved fluid flow and reducing the strength of secondary electromagnetic fields
Implementation Method 3
a NMR tool may be used to take measurements of the formation using one or more antennas
Data Source
AI summary
An example method for generating measurements using a downhole tool may comprise generating a magnetic field using a magnetic field source coupled to a tool body. An electromagnetic signal may be transmitted from an antenna coupled to the tool body and around which at least one radial projection is positioned and tilted with respect to a longitudinal axis of the tool body. The method may also include receiving a response to the transmitted electromagnetic signal.