Transverse Toroid Transmitter for Multi-Depth Resistivity Logging
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Solution Overview
Problem
Conventional oil well logging methods face challenges in accurately estimating electrical resistivity properties of earth formations, particularly due to the hostile drilling environment and limitations in depth of investigation.
Innovation Solution
The use of transverse toroids with single coil antennas positioned on a carrier, which includes multiple transmitter toroid pairs operating at different frequencies to estimate electrical resistivity properties by varying the amplitude and distance of the toroids from a receiver, allowing for multiple depths of investigation without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional logging methods use a single transmitter, then the device complexity is low, but the depth of investigation is limited to a single depth
Solution Approach 1:
The system dynamically switches between multiple transmitter configurations (different spacings and orientations) to achieve variable depths of investigation. The transmitters can be selectively activated at different spacings (e.g., 10ft, 20ft, 30ft) and orientations (radial, axial, transverse) to adapt to different measurement requirements without permanently installing multiple fixed configurations.
Solution Approach 2:
A single logging tool incorporates multiple transmitter spacings and orientations within one device, making it universally capable of performing multiple depth investigations. The tool can function as both a shallow-depth investigator (using closer spacings) and a deep-depth investigator (using larger spacings), eliminating the need for multiple specialized tools.
2Measurement precision
If multiple transmitters are used to achieve multiple depths of investigation, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The logging tool is segmented into multiple transmitter units with different spacings and orientations, each capable of independent operation. This segmentation allows the system to select appropriate segments (transmitters) based on the required depth of investigation, achieving precise measurements at multiple depths while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The system changes operational parameters (transmitter spacing, orientation, and activation sequence) to achieve different depths of investigation. By varying these parameters rather than physically reconfiguring the entire device, the system maintains measurement precision across multiple depths while minimizing device complexity.
3Adaptability or versatility
If additional hardware is added to achieve multiple depths of investigation, then the adaptability improves, but the ease of operation deteriorates
Solution Approach 1:
Multiple transmitter functions (different spacings and orientations) are merged into a single integrated logging tool. This consolidation allows the operator to control multiple investigation depths from one device using a unified interface, improving ease of operation compared to managing multiple separate tools while maintaining high adaptability through the combined functionality.
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 provides robust and accurate estimation of electrical resistivity properties across various depths, offering improved resolution and coverage, even in hostile environments, by utilizing the toroid's ability to confine and guide magnetic fields effectively.
Implementation Method 1
a receiver toroid on the carrier, the receiver toroid being positioned transversely on the carrier and including a single coil antenna
Implementation Method 2
by utilizing the toroid's ability to confine and guide magnetic fields effectively
Data Source
AI summary
An apparatus and method for estimating a parameter of interest of an earth formation, particularly relating to borehole logging methods and apparatuses for estimating electrical resistivity properties at multiple depths of investigation. The apparatus may include two or more transmitters for introducing electrical current to the earth formation. The apparatus may include a controller configured to deliver an electrical signal to the two or more transmitters either simultaneously or sequentially. The controller may deliver an electrical signal to two or more transmitters at the same frequency for estimating depth of investigation. The apparatus may include one or more receivers responsive to electric signals from the earth formation at one or more frequencies to provide data from one or more depths of investigation. The method may include steps for using the apparatus to obtain data that may be used to estimate the parameter of interest.