Azimuthal Casing Inspection Tool with Circumferential Sensors
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Solution Overview
Problem
Conventional downhole logging tools for casing inspection face challenges with mechanical complexity, high manufacturing and maintenance costs, and operational reliability issues due to the use of bow-spring/pad mounted designs and motorized rotation mechanisms for azimuthal casing thickness measurement.
Innovation Solution
A downhole logging tool with a housing supported by a cable, featuring circumferentially-spaced transmitters and receivers that generate and sense magnetic fields with azimuthal sensitivity, utilizing electronic circuitry to determine casing characteristics, and a transceiver with radially extending fins and insulating segments for improved measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bow-spring/pad mounted designs are used for azimuthal casing thickness measurement, then measurement capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The tool divides the circumferential measurement capability into multiple discrete sensor pairs positioned at different azimuthal angles around the tool body. Each sensor pair measures casing thickness in a specific azimuthal direction, and the combination of multiple segmented measurements provides complete azimuthal coverage without requiring mechanical movement or complex mounting mechanisms.
2Measurement precision
If motorized rotation mechanisms are used for azimuthal casing thickness measurement, then measurement capability is improved, but reliability decreases due to moving parts
Solution Approach 1:
The patent replaces the mechanical rotation system with a stationary electromagnetic sensing array. Instead of physically rotating a single sensor to scan different azimuthal positions, multiple sensor pairs are fixed at different angular positions around the tool, eliminating all moving parts while achieving the same measurement objective through simultaneous multi-directional sensing.
3Measurement precision
If conventional remote-field eddy current techniques are used, then casing inspection is achieved, but only circumferential average measurement is obtained without azimuthal sensitivity
Solution Approach 1:
The patent applies local quality by positioning sensor pairs at specific azimuthal locations around the tool body, with each sensor pair optimized to measure casing properties in its specific directional sector. This creates localized measurement zones with different azimuthal sensitivities, allowing the system to capture spatial variations in casing thickness around the circumference rather than providing only a uniform average.
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 provides accurate azimuthal casing thickness measurements with reduced mechanical complexity and maintenance costs, enhancing operational reliability and sensitivity, allowing for precise characterization of well casings.
Implementation Method 1
A transmitter is positioned in the housing and operable to generate a magnetic field
Implementation Method 2
Plural receivers are positioned in the housing in circumferentially-spaced apart relation and are operable to sense the magnetic field with azimuthal sensitivity
Implementation Method 3
This component of the propagating magnetic field that penetrates through the casing wall and propagates outside the casing is the remote field. After penetrating the casing wall, the remote field attenuates due primarily to the media outside the casing
Data Source
AI summary
Various downhole logging tools and methods of using and making the same are disclosed. In one aspect, a downhole logging tool for inspecting a well casing is provided that includes a housing adapted to be supported in the well casing by a support cable. A transmitter is positioned in the housing and operable to generate a magnetic field. Plural receivers are positioned in the housing in circumferentially-spaced apart relation and are operable to sense the magnetic field with azimuthal sensitivity. Electronic circuitry is operatively coupled to the receivers to determine a parameter of the sensed magnetic field and determine a characteristic of the well casing based on the parameter.