NMR Logging Probe Multi-Layer Magnet Antenna Excitation
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Solution Overview
Problem
Nuclear magnetic resonance logging instrument probes are limited to detecting signals in radial and axial depth dimensions, unable to perform multi-directional sensitive region detection in the circumferential direction.
Innovation Solution
A nuclear magnetic resonance logging instrument probe with a cylindrical probe skeleton and evenly distributed magnet assemblies, each with multiple layers of radially magnetized magnets and independently fed antennas, allowing for excitation of different antennas to detect stratum information at various azimuth angles, enabling three-dimensional detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single cylindrical magnet with an encircling antenna is used, then the probe structure is simple and can perform 360-degree excitation, but the detection capability is limited to radial and axial dimensions only, unable to detect multi-directional sensitive regions in the circumferential direction
Solution Approach 1:
The single cylindrical magnet is segmented into multiple magnet assemblies distributed around the probe skeleton. Each magnet assembly includes multiple layers of magnets with alternating magnetization directions. This segmentation enables independent antenna excitation for detecting sensitive regions at different azimuth angles, transforming the detection capability from 2D (radial-axial) to 3D (including circumferential direction) while maintaining manageable structural complexity through modular design
Solution Approach 2:
The invention adds the circumferential dimension to the detection capability by arranging multiple magnet assemblies and antennas around the probe skeleton. By independently exciting different antennas, the system can detect sensitive regions at different azimuth angles, achieving three-dimensional detection capability (radial, axial, and circumferential dimensions) from the original two-dimensional detection
2Manufacturing precision
If multiple layers of magnets with alternating magnetization directions are used in each magnet assembly, then the magnetic field strength is evenly distributed at different axial depths, but the manufacturing complexity increases
Solution Approach 1:
Each magnet assembly contains multiple layers of magnets with alternating magnetization directions (first direction, second direction opposite to first). This local quality variation in magnetization direction enables even distribution of magnetic field strength at different axial depths. The alternating pattern creates complementary magnetic fields that balance the overall field distribution, achieving uniform detection sensitivity throughout the axial measurement range while maintaining systematic manufacturing procedures
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 design enhances circumferential resolution and allows for stratum detection in three dimensions, improving the probe's performance by evenly distributing magnetic field strength and enabling detection at different azimuth angles.
Implementation Method 1
the magnet can form a static magnetic field for polarizing a self-spinning hydrogen proton
Implementation Method 2
the antenna can transmit a radio frequency field for turning the self-spinning hydrogen proton around
Implementation Method 3
prompting the self-spinning hydrogen proton to precess along the static magnetic field, resulting in that nuclear magnetic resonance induction signals
Data Source
AI summary
The present invention provides a nuclear magnetic resonance logging instrument probe with multi-layered magnet and an antenna excitation method, the nuclear magnetic resonance logging instrument probe includes a probe skeleton, multiple magnet assemblies and a plurality of antennas; the probe skeleton is of a cylindrical shape, multiple magnet assemblies are distributed in the circumferential direction of the probe skeleton; the magnet assembly includes at least two layers of magnet arranged from top to bottom, the magnet is magnetized in a radial direction, two adjacent layers of magnet are magnetized in opposite directions; an antenna is arranged outside each magnet assembly, multiple antennas are independently fed. In the nuclear magnetic resonance logging instrument probe and antenna excitation method, through exciting different antennas, detection of stratum information at different azimuth angles is realized, which improves circumferential resolution of the probe, realize stratum detection in three dimensions along radius, axis and circumference.