Modular Electromagnetic Logging Antenna System
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Solution Overview
Problem
Conventional electromagnetic logging tools lack azimuthal sensitivity, making it difficult to distinguish between conductive layers above and below in high-angle or horizontal wells, limiting their effectiveness in well placement and formation evaluation applications.
Innovation Solution
A modular downhole electromagnetic system with multiple antenna modules spaced apart by spacer modules, providing an electrical pathway and allowing for increased depth of investigation, and incorporating replaceable antennas with varying magnetic moments to enhance directional measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If axial transmitter and receiver antennas are used in conventional electromagnetic logging tools, then the tool structure is simple and easy to manufacture, but the tool lacks azimuthal sensitivity and cannot distinguish directional information about conductive layers
Solution Approach 1:
The antenna system is segmented into multiple independent antenna modules, each with specific orientation (axial, tilted, or transverse). These modules can be selectively combined to create different measurement configurations, enabling azimuthal sensitivity while maintaining modular simplicity in design and manufacturing.
Solution Approach 2:
Different antenna modules have different local properties - axial antennas provide depth information, tilted antennas provide directional information, and transverse antennas provide azimuthal sensitivity. By placing antennas with specific orientations at specific locations, the system achieves comprehensive measurement capability without requiring all antennas to be complex.
2Measurement precision
If antenna spacing is increased to improve depth of investigation, then formation evaluation capability is enhanced, but the physical length of the tool increases
Solution Approach 1:
The tool is divided into multiple modular sections with antennas spaced at optimal intervals. This segmentation allows the total tool length to be adjusted by adding or removing modules, enabling flexible configuration that balances depth of investigation requirements with practical tool length constraints for different well conditions.
3Measurement precision
If multiple antenna modules with different orientations are incorporated to provide directional measurements, then formation evaluation accuracy is improved, but the device complexity and number of components increase
Solution Approach 1:
Each antenna module is designed with universal connectivity features (such as standardized connectors and mounting interfaces) that allow the same module type to serve multiple functions depending on its orientation and position in the tool string. This multi-functionality reduces the total number of different component types needed while achieving comprehensive measurement capability.
Solution Approach 2:
The antenna modules are designed to be dynamically configurable - they can be added, removed, or repositioned based on specific measurement requirements. This dynamic configuration allows the system to adapt to different well conditions and measurement needs without requiring a completely different tool design, thereby managing complexity through flexibility rather than fixed 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
The modular system enhances directional sensitivity, providing more accurate formation evaluation and well placement data by increasing the spacing between antennas and using replaceable antennas with different magnetic moments, thereby improving the ability to distinguish between conductive layers in complex well geometries.
Implementation Method 1
Electromagnetic logging tools, including electromagnetic induction and wave propagation logging tools, are used to determine the electrical properties of formations surrounding a borehole
Implementation Method 2
electromagnetic induction and wave propagation logging tools
Data Source
AI summary
A downhole electromagnetic modular system has two or more antenna modules incorporated into a drill string, each antenna module comprising an antenna sub and an antenna. The antenna modules may be spaced apart by one or more spacer modules, battery modules, spacer-battery modules, and/or downhole tools. The connected modules (and/or downhole tools) provide an electrical pathway throughout the modular system. An antenna module may have an inner connector formed on its antenna sub between the antenna of that antenna module and a retainer of that antenna sub. An antenna module may have two antenna groups located towards opposite ends of the antenna module and spaced apart by more than half the length of the antenna module. If an antenna group has more than one antenna, those antennas may be co-located or in proximity to one another. A probe may be held fixed by the retainer of the inner pin connector.