Induction Logging Tool Electrode and Multi-Frequency Focusing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electromagnetic induction well logging techniques are limited in measuring vertical conductivity and anisotropy of earth formations due to tool eccentricity and coil misalignment effects, which affect the accuracy of resistivity measurements.
Innovation Solution
A logging tool with a non-conductive mandrel, inclined transmitter and receiver antennas, and electrodes forming a conductive path through the borehole fluid, combined with multifrequency focusing (MFF) to reduce eccentricity and misalignment errors, enabling accurate determination of resistivity properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electromagnetic induction well logging techniques are used, then horizontal conductivity can be measured, but vertical conductivity and anisotropy cannot be accurately measured due to tool eccentricity and coil misalignment effects
Solution Approach 1:
The logging tool is divided into multiple independent components: multiple transmitter coils oriented in different directions, multiple receiver coils, and separate processing systems for each component. This segmentation allows independent measurement and processing of different conductivity components, enabling accurate determination of both horizontal and vertical conductivity despite tool eccentricity and misalignment.
Solution Approach 2:
The patent employs asymmetric coil arrangements where transmitter and receiver coils are oriented at specific non-standard angles relative to the tool axis. This asymmetric configuration creates measurement patterns that are sensitive to directional conductivity variations, allowing the system to detect and compensate for eccentricity and misalignment effects while measuring both horizontal and vertical conductivity components.
2Adaptability or versatility
If multi-component measurements are used to determine formation resistivities and petrophysical parameters, then more comprehensive formation properties can be measured, but non-formation parasite effects from tool eccentricity and coil misalignment increase
Solution Approach 1:
The patent converts the harmful effects of tool eccentricity and coil misalignment into beneficial measurement capabilities by using these same geometric deviations to create asymmetric measurement patterns. The processing system interprets the signal variations caused by eccentricity and misalignment as information about formation anisotropy and vertical conductivity, thereby transforming measurement errors into useful geological information.
Solution Approach 2:
The system employs iterative processing that compares measurements from multiple coil configurations and uses this feedback to separate formation signals from tool-induced artifacts. The processing algorithm continuously refines the separation of formation conductivity components from eccentricity and misalignment effects, enabling accurate measurement of multiple formation properties while minimizing non-formation parasite effects.
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 solution effectively compensates for tool eccentricity and misalignment, improving the accuracy of resistivity measurements by minimizing the impact of non-formation parasite effects, thereby enhancing the reliability of resistivity data obtained from multi-component resistivity measurements.
Implementation Method 1
One or more transmitter coils are energized by an alternating current. The oscillating magnetic field produced by this arrangement results in the induction of currents in the formations
Implementation Method 2
These currents, in turn, contribute to the voltage induced in one or more receiver coils
Data Source
AI summary
A multicomponent induction logging tool uses a nonconducting mandrel. A central conducting member including wires that electrically connect at least one of the antennas to another of the antennas. Electrodes disposed about the transmitter antenna form a conductive path through a borehole fluid to the central conducting member.