Azimuthal Resistivity Tool With Orthogonal Wire Coils
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Solution Overview
Problem
Existing resistivity logging methods face challenges in accurately measuring azimuthal resistivity in formations with resistivity anisotropy, which can lead to misinterpretation of hydrocarbon-bearing formations.
Innovation Solution
The development of a resistivity measuring tool with a transverse receiving antenna and an axial transmitting antenna, capable of making azimuthal electromagnetic resistivity measurements by transmitting electromagnetic waves and receiving voltage signals related to formation parameters, while compensating for formation resistivity anisotropy effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional resistivity logging methods are used, then the measurement process is simple, but the measurement precision is reduced due to formation resistivity anisotropy
Solution Approach 1:
The receiving antenna is segmented into multiple wire coils (first wire coil, second wire coil, third wire coil) with different orientations. Each wire coil is configured to generate a magnetic moment in a specific direction (first, second, and third orthogonal directions respectively), allowing the tool to measure resistivity in multiple azimuthal directions simultaneously. This segmentation enables accurate azimuthal resistivity measurements by capturing the anisotropic response of the formation in different orientations.
Solution Approach 2:
The invention transitions from conventional single-axis resistivity measurement to three-dimensional azimuthal measurement by adding wire coils oriented in multiple orthogonal directions. The first wire coil measures resistivity in the first direction, the second wire coil in the second direction, and the third wire coil in the third direction, creating a three-component measurement system that fully characterizes the anisotropic formation properties in all spatial dimensions.
2Measurement precision
If multiple wire coils are added to measure azimuthal resistivity, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The multiple wire coils are integrated into a single receiving antenna assembly that performs multiple measurement functions simultaneously. The first wire coil, second wire coil, and third wire coil collectively provide three-component resistivity measurement capability, enabling the tool to characterize formation anisotropy, detect bed boundaries, and identify hydrocarbon-bearing formations through a single unified antenna structure rather than requiring separate measurement systems.
Solution Approach 2:
The invention merges multiple wire coils with different orientations into a single integrated receiving antenna system. The first wire coil, second wire coil, and third wire coil are combined within the same antenna body, sharing common structural support and signal processing infrastructure. This merging reduces the overall device complexity compared to using separate antennas for each measurement direction, while maintaining the ability to capture azimuthal resistivity variations.
3Measurement precision
If transverse receiving antenna with orthogonal wire coils is used, then the detection of bed boundaries is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
Each wire coil is designed with specific local quality characteristics - the first wire coil is optimized for measuring resistivity in the first direction, the second wire coil for the second direction, and the third wire coil for the third direction. Each coil's winding geometry, turn density, and orientation are locally optimized for its specific measurement function, allowing the system to achieve high bed boundary detection resolution through specialized local configurations rather than requiring uniform high precision across the entire antenna assembly.
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 solution enables more accurate azimuthal resistivity measurements, effectively reducing the impact of formation resistivity anisotropy and enhancing the detection and resolution of adjacent bed boundaries, thereby improving the identification of hydrocarbon-bearing formations.
Implementation Method 1
The transmitting antenna is configured to transmit electromagnetic energy into the formation
Implementation Method 2
the wire coil is configured to generate a magnetic moment orthogonal to the tool body longitudinal axis
Data Source
AI summary
A resistivity measuring tool used in a drillstring having a drill bit on a distal end for drilling a wellbore in a formation includes a tool body having a longitudinal axis, a transmitting antenna, and a receiving antenna. The receiving antenna includes an antenna body having a longer axis disposed longitudinally in the tool body, and a wire coil having a central axis disposed around the antenna body, wherein the wire coil central axis is substantially perpendicular to the longer axis of the antenna body, and wherein the wire coil is configured to generate a magnetic moment orthogonal to the tool body longitudinal axis. The transmitting antenna is configured to transmit electromagnetic energy into the formation and induce a voltage signal related to a parameter of the formation in the receiving antenna.