Slim Sonic Logging Tool Layout for Azimuthal and Resonance Measurement
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Solution Overview
Problem
Slim hole sonic tools face limitations in azimuthal receiver count due to space constraints, leading to reduced measurement resolution and difficulty in matching receiver sensitivity, and struggle with borehole resonant modes that require specific directional measurements for accurate cement condition evaluation.
Innovation Solution
A slim hole acoustic tool integrating a borehole resonance mode measurement module and a pitch-catch measurement module, with a monopole transmitter and dipole receivers, allowing for 360-degree azimuthal sampling and independent or combined operation to measure different types of borehole sonic logging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of azimuthal receivers is increased to improve measurement azimuthal sampling and angular resolution, then measurement precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The tool divides the measurement function into two independent modules: a borehole resonance mode measurement module with fewer receivers for vertical resolution, and a pitch-catch measurement module with multiple azimuthal receivers for angular resolution. This segmentation allows each module to be optimized for its specific function without compromising the other.
Solution Approach 2:
The patent transitions from traditional horizontal azimuthal sampling to vertical sampling by using closely spaced receivers in the borehole resonance mode module. This dimensional change in sampling approach allows high vertical resolution without requiring numerous azimuthal receivers, thus reducing device complexity.
2Measurement precision
If multiple receivers are added to improve measurement capability, then measurement precision is improved, but matching receivers with identical sensitivity becomes more difficult
Solution Approach 1:
By separating the tool into two modules with different receiver configurations, the patent avoids the need to match multiple receivers within the same module. The borehole resonance mode module uses a limited number of receivers for vertical sampling, while the pitch-catch module uses multiple receivers for azimuthal sampling, eliminating the matching complexity.
Solution Approach 2:
The patent employs a rotating mechanism that allows the tool to dynamically sample azimuthal directions over time. This dynamic approach replaces the need for multiple statically positioned receivers with identical sensitivity, as the same receivers can be rotated to different angular positions during measurement.
3Measurement precision
If transmitter-to-receiver distance is reduced to improve vertical cement map resolution, then measurement precision is improved, but signal interference from tubing reverberation increases
Solution Approach 1:
The patent separates the measurement functions into two specialized modules: the borehole resonance mode module optimized for vertical resolution with close transmitter-receiver spacing, and the pitch-catch module designed to handle tubing reverberation issues. This segmentation allows each module to address specific challenges without compromise.
Solution Approach 2:
The patent introduces an acoustic isolation mechanism as an intermediary between the transmitter and receivers in the borehole resonance mode module. This intermediary structure prevents direct acoustic coupling and reduces tubing reverberation interference, allowing close transmitter-receiver spacing without the harmful effects of strong reverberation signals.
4Adaptability or versatility
If the tool is designed for slim hole operation with limited space, then adaptability to slim hole environments is improved, but the number of receivers and measurement capability are reduced
Solution Approach 1:
The patent divides the tool into two specialized modules, each optimized for specific measurement functions. The borehole resonance mode module with fewer receivers provides vertical sampling capability, while the pitch-catch module with multiple receivers provides azimuthal sampling capability. This segmentation allows the tool to maintain comprehensive measurement capability within a compact slim-hole-compatible form factor.
Solution Approach 2:
The patent compensates for the limited number of physical receivers by implementing vertical sampling through the borehole resonance mode module. This dimensional change in sampling strategy allows the tool to achieve complete formation characterization without requiring a large number of receivers, thus maintaining measurement capability within slim hole space constraints.
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
Enhances vertical cement map resolution and accuracy by reducing transmitter-to-receiver distance, enabling independent or combined module operation to overcome spatial aliasing and interference, and providing comprehensive cement condition evaluation.
Implementation Method 1
borehole resonance mode measurement module... to excite casing breathing modes
Implementation Method 2
dense acoustic array for 360-degree azimuthal sampling... to perform traditional borehole sonic logging
Data Source
AI summary
The invention relates to a slim sonic logging tool with multiple modules for borehole resonance mode and pitch-catch measurement, comprising a cylindrical housing, a monopole transmitter, a pair of cross-dipole transmitters and a ring of receivers disposed between the monopole transmitter and the pair of cross-dipole transmitters within the cylindrical housing, the ring of receivers, being axially around a circumference of the first cylindrical housing.