Electromagnetic Imager Mud Angle Calibration via Azimuthal Variation
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Solution Overview
Problem
Existing techniques for identifying the mud angle in electromagnetic imager tools are often inaccurate, leading to poor image quality and contrast due to the mud effect, and require inefficient direct mud measurements or additional tool components, which are costly and complex.
Innovation Solution
A method to accurately identify the mud angle based on variations in mud effect corrected measurements made by the electromagnetic imager tool, eliminating the need for direct mud measurements and simplifying the tool design by using mud effect removal techniques like Z90 processing with estimated mud angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct mud measurements are taken to identify mud angle, then measurement accuracy may be improved, but time efficiency deteriorates and tool complexity increases
Solution Approach 1:
The patent extracts the mud angle identification process from the main logging operation by using a separate calibration run where the tool is positioned against a known reference (borehole wall or calibration target). This allows mud angle to be determined without requiring direct mud measurements during actual logging, thereby saving time while maintaining accuracy through the calibration-based approach.
Solution Approach 2:
The patent performs mud angle calibration as a preliminary action before actual formation logging. By conducting the calibration run first to establish the mud angle, the system prepares the necessary parameter in advance, eliminating the need for time-consuming direct mud measurements during the productive logging phase.
2Measurement precision
If additional tool components like mud cells are added to directly measure mud properties, then measurement accuracy improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent makes the electromagnetic imager tool multi-functional by enabling it to perform both formation imaging and mud angle calibration using the same measurement units. The tool uses its existing azimuthal sensitivity and measurement capabilities for dual purposes, eliminating the need for dedicated mud measurement components while maintaining measurement accuracy through proper calibration procedures.
Solution Approach 2:
The electromagnetic imager tool serves itself by using its own measurement units and processing capabilities to determine mud angle. The system leverages its inherent azimuthal sensitivity and impedance measurement abilities to calibrate and identify mud angle without requiring external or additional specialized components.
3Productivity
If inaccurate mud angle estimates are used in mud effect removal techniques, then processing speed is maintained, but image quality and contrast deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the mud angle is iteratively refined through calibration runs and compared against reference measurements. The system uses the azimuthal variation in measured impedance as feedback to adjust and optimize the mud angle estimate, ensuring high accuracy while maintaining efficient processing through automated algorithms.
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 approach provides more accurate mud angle estimates, improving image quality and reducing resource consumption by eliminating the need for direct mud measurements and complex tool designs.
Implementation Method 1
electromagnetic imager tool operating to log a wellbore in a formation... tool measurements made through one or more measurement units with azimuthal sensitivity
Data Source
AI summary
Aspects of the subject technology relate to systems and methods for identifying a mud angle associated with an electromagnetic imager tool based on variations in mud effect removed quantities of tool measurements made by the electromagnetic imager tool. Tool measurements made through one or more measurement units of an electromagnetic imager tool can be received. The one or more measurement units can have azimuthal sensitivity and the electromagnetic imager tool can operate to log a wellbore in a formation in making the measurements. One or more mud effect removal techniques can be applied to the tool measurements across a plurality of mud angle estimates to generate mud effect removed quantities for the one or more measurement units across the plurality of mud angle estimates. A mud angle associated with the electromagnetic imager tool can be identified from the plurality of mud angle estimates based on an amount of variation between the mud effect removed quantities across the one or more measurement units for each of the plurality of mud angle estimates.