NMR Pulse Sequences with Interacting Shells for Borehole Logging
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Solution Overview
Problem
Conventional NMR systems face inefficiencies due to the need for idle time while waiting for shells to reach thermal equilibrium, leading to increased measurement time and reduced signal-to-noise ratio (SNR) in borehole logging applications.
Innovation Solution
Implementing a method that applies multiple NMR pulse sequence segments at different frequencies to generate resonant signals in multiple shells simultaneously, allowing for the detection of NMR properties before the first shell reaches thermal equilibrium, thereby reducing idle time and enhancing SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the NMR system waits for the shell to reach thermal equilibrium before initiating the next pulse sequence, then the measurement accuracy is improved, but the measurement time increases significantly
Solution Approach 1:
The patent divides the measurement process into multiple segments by applying pulse sequences to multiple shells simultaneously. Each shell is excited at a different frequency, allowing parallel measurement of NMR properties across different depth regions. This segmentation enables continuous data acquisition without waiting for complete thermal equilibrium recovery, thereby reducing total measurement time while maintaining accuracy through multiple measurements.
Solution Approach 2:
The patent introduces a frequency dimension to differentiate between shells. By assigning different excitation frequencies to different shells, the system can simultaneously measure multiple shells without interference. This dimensional approach allows parallel processing of multiple measurement channels, eliminating the sequential waiting time required in conventional single-frequency approaches.
2Measurement precision
If the NMR system waits for thermal equilibrium, then the signal-to-noise ratio is improved, but the system sits idle reducing productivity
Solution Approach 1:
The patent implements continuous useful action by initiating pulse sequences on subsequent shells before previous shells complete their thermal equilibrium. The system continuously acquires NMR data from multiple shells in parallel, eliminating idle time between measurements. This continuous operation maintains signal quality through multiple measurements while maximizing system productivity.
Solution Approach 2:
The patent applies preliminary action by preparing and initiating pulse sequences for multiple shells in advance. The system pre-configures different excitation frequencies and pulse parameters for each shell, allowing immediate initiation of measurements without waiting for complete equilibrium recovery. This preliminary preparation enables seamless transition between measurements.
3Loss of time
If multiple pulse sequence segments are applied at different frequencies to multiple shells simultaneously, then measurement time is reduced, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing the NMR system to perform multiple functions simultaneously. The same hardware components (transmitter, receiver, processing unit) are used to excite and measure multiple shells at different frequencies. This multi-functional approach reduces the need for additional specialized equipment while enabling parallel measurements, thereby limiting the increase in device complexity.
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 speeds up NMR measurements and improves the signal-to-noise ratio by allowing for continuous data acquisition without waiting for thermal equilibrium, reducing measurement time and increasing accuracy in NMR property determination.
Implementation Method 1
Nuclear magnetic resonance (NMR) can be used to determine properties of a substance. An NMR procedure typically includes applying a static magnetic field to the substance. The static magnetic field generates an initial magnetization of atomic nuclei within the substance. Then, an NMR system is used to apply an oscillating magnetic field at a particular frequency to the substance. The oscillating field is composed of a sequence of pulses that tip the magnetization of the atomic nuclei away from the initial magnetization.
Implementation Method 2
applying a static magnetic field to the substance. The static magnetic field generates an initial magnetization of atomic nuclei within the substance
Implementation Method 3
an NMR system is used to apply an oscillating magnetic field at a particular frequency to the substance. The oscillating field is composed of a sequence of pulses that tip the magnetization of the atomic nuclei away from the initial magnetization
Implementation Method 4
pulses and the static field interact with the nuclei to produce a resonant signal composed of 'echoes' within at least a portion of the substance
Data Source
AI summary
A method and system for determining a nuclear magnetic resonance (NMR) property are described herein. The method includes applying a static magnetic field to a substance and applying an NMR pulse sequence to the substance. The NMR pulse sequence comprises a first pulse sequence segment applied at a first frequency to a shell and a second pulse sequence segment applied at a second frequency. The first pulse sequence segment generates a resonant signal in the shell and the second pulse sequence segment generates a characteristic within the resonant signal. The resonant signal is detected and an NMR property is determined using the characteristic within the detected resonant signal.