3D NMR Logging Probe Antenna Segmentation
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Solution Overview
Problem
Existing nuclear magnetic resonance logging instrument probes can only detect signals in radial and axial depth dimensions, lacking the capability to detect signals in the circumferential multi-azimuth sensitive area.
Innovation Solution
A three-dimensional nuclear magnetic resonance logging instrument probe is designed with four uniformly distributed magnets along the circumference, each equipped with independently fed strip-type antennas, allowing for stratum information detection at different azimuth angles by exciting specific antennas, thereby enhancing the circumferential recognition capability and enabling three-dimensional stratum detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a column-shaped magnet with 360° antenna excitation is used, then the nuclear magnetic resonance logging instrument can perform multi-frequency multi-slice measurement without detection blind zones, but it only obtains average signals from the 360-degree stratum and cannot detect signals in the circumferential multi-azimuth sensitive area
Solution Approach 1:
The patent divides the single 360° antenna system into multiple independently fed antennas (e.g., 8 antennas arranged at different azimuths). Each antenna can be excited separately to detect signals from specific azimuth directions, thereby segmenting the detection space to preserve circumferential multi-azimuth signal information while maintaining comprehensive detection coverage.
Solution Approach 2:
The patent transitions from a single-dimension (radial) or two-dimension (radial-axial) detection system to a three-dimensional detection system by adding circumferential azimuth detection capability. Multiple antennas are positioned at different circumferential angles, enabling the system to detect signals in three spatial dimensions (radial, axial, and circumferential) simultaneously.
2Measurement precision
If multiple independently fed antennas are positioned at different circumferential angles, then three-dimensional stratum detection capability is achieved, but the device complexity increases
Solution Approach 1:
The patent designs the multiple antennas to share common signal processing and control systems, allowing a single set of electronics to serve multiple detection functions. The system can selectively excite different antenna combinations based on measurement requirements, making the complex multi-antenna system versatile and manageable through unified control.
Solution Approach 2:
The patent combines multiple antennas and magnets into an integrated probe assembly where components are spatially arranged and functionally coordinated. The antennas are positioned around the magnet assembly with shared mounting structures and signal processing pathways, merging what could be separate independent systems into a unified multi-functional instrument.
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 probe achieves improved circumferential recognition and enables three-dimensional detection by combining radial, axial, and circumferential stratum information, providing comprehensive downhole data through various antenna excitation modes.
Implementation Method 1
the magnet can form a static magnetic field for polarizing a spin hydrogen proton
Implementation Method 2
the antenna can emit a radio frequency field for reversing the spin hydrogen proton
Implementation Method 3
after the radio frequency field is removed, the spin hydrogen proton starts to precess along the static magnetic field, and thereby generates an nuclear magnetic resonance inductive signal
Data Source
AI summary
The present invention provides a three-dimensional nuclear magnetic resonance logging instrument probe, a logging instrument and an antenna excitation method, where the probe includes: a probe framework, a magnet and an antenna; four magnets are uniformly distributed along a circumference of the probe framework, the magnets are magnetized in a radial direction of the probe framework, two magnets placed opposite to each other are magnetized from outside to inside, and the other two magnets placed opposite to each other are magnetized from inside to outside; in the probe framework, each of the magnets is provided with independently fed antennas; antennas corresponding to each of the magnets comprise a left antenna provided on one side of the corresponding magnet and a right antenna provided on the other side of the corresponding magnet; the left antenna and the right antenna corresponding to each magnet are electrically connected.