Downhole NMR Tool Side-Looking Magnetic Field Configuration
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Solution Overview
Problem
NMR logging tools face challenges in maintaining accurate measurements while moving within a wellbore, as existing technologies distort the magnetic fields required for nuclear magnetic resonance measurements.
Innovation Solution
The NMR logging tool is designed to operate in a side-looking mode with a static magnetic field generated in a substantially longitudinal direction, allowing for NMR measurements to be taken while moving, using a configuration of magnetic elements and a radio frequency coil that maintains a uniform magnetic field and enhances signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the NMR tool is moved within the wellbore to improve productivity, then measurement speed increases, but magnetic field distortion occurs reducing measurement precision
Solution Approach 1:
The patent applies dynamics by making the magnetic field configuration adaptive to tool motion. The magnetic elements are arranged to generate a longitudinal magnetic field that remains stable during tool movement, transforming the static field requirement into a dynamic solution that maintains field uniformity while the tool moves through the wellbore.
Solution Approach 2:
The patent changes the dimensional orientation of the magnetic field from the traditional transverse configuration to a longitudinal configuration aligned with the tool axis. This dimensional change allows the magnetic field to extend along the length of the tool, creating a larger uniform field region that maintains stability during movement and improves measurement accuracy while moving.
2Productivity
If the magnetic field configuration is changed to enable movement, then productivity improves, but signal-to-noise ratio may deteriorate
Solution Approach 1:
By reorienting the magnetic field from transverse to longitudinal configuration, the patent creates an extended field region along the tool axis. This dimensional change increases the interaction volume between the magnetic field and formation fluids, thereby enhancing the NMR signal strength while maintaining the ability to measure during tool movement.
Solution Approach 2:
The longitudinal magnetic field configuration serves multiple functions simultaneously: it enables the tool to measure while moving, maintains field uniformity across the measurement zone, and enhances signal-to-noise ratio by increasing the effective measurement volume. This multi-functional design resolves the contradiction between movement capability and signal quality.
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
Enables accurate NMR measurements to be taken while the tool is moving, providing reliable characterization of subterranean formations by maintaining a uniform magnetic field and improving signal quality.
Implementation Method 1
a magnetic element located within the tool body configured to generate a static magnetic field (B0) in a longitudinal direction
Implementation Method 2
a radio frequency coil located within the tool body and configured to generate a radio frequency magnetic field (B1)
Implementation Method 3
measures the induced magnet moment of hydrogen nuclei (protons) contained within the fluid-filled pore space of a formation
Data Source
AI summary
Nuclear magnetic resonance (NMR) method, system, and sensing device for downhole measurements. The NMR device for characterizing a subterranean zone includes a tool body, a magnetic element, and a radio frequency coil. The tool body includes an uphole end and a downhole end, where a longitudinal axis extends through the uphole end and downhole end. The magnetic element is located within the tool body and generates a static magnetic field (B0) in a longitudinal direction at a region of the subterranean zone. The radio frequency coil is located within the tool body and generates a radio frequency magnetic field (B1). The magnetic element and the radio frequency coil enable a side-looking NMR mode.