Electroacoustic Conductivity Measurement Through Casing
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Solution Overview
Problem
Current methods for characterizing earth formations surrounding boreholes lack effectiveness in estimating parameters such as resistivity, porosity, and permeability using electroacoustic techniques, particularly in providing accurate and efficient data during the drilling process.
Innovation Solution
A method and apparatus utilizing a constant magnetic field and a harmonic magnetic field applied to a metallic surface in communication with the earth formation, generating acoustic waves that are sensed to estimate parameters like characteristic frequency and conductivity, enabling more precise formation evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional electroacoustic logging methods are used after borehole drilling, then formation parameters can be characterized, but the timing is delayed and productivity is reduced
Solution Approach 1:
The patent applies preliminary action by implementing formation evaluation measurements during the drilling process itself, rather than waiting until after drilling is complete. The logging tool is integrated with the drilling system to perform electroacoustic measurements in real-time, allowing formation parameters to be assessed before the drilling operation concludes, thereby eliminating the time delay inherent in conventional post-drilling logging methods
2Measurement precision
If conventional logging methods are used, then formation parameters can be measured, but measurement precision and accuracy are insufficient
Solution Approach 1:
The patent merges previously separate measurement functions into a single integrated logging tool that simultaneously performs both electroacoustic measurements and acoustic wave generation/detection. By combining the magnetic field generation capabilities with acoustic transduction functions in one device, the system achieves higher measurement precision for formation parameters while avoiding the complexity of multiple separate tools
Solution Approach 2:
The logging tool exhibits multi-functionality by capable of generating magnetic fields, detecting acoustic waves, and measuring formation parameters all through a single device. This universal tool can perform multiple measurement tasks including characterizing porosity, permeability, and other formation properties, thereby improving measurement precision without proportionally increasing device complexity
Data Source
AI summary
The present disclosure relates to methods and apparatuses for evaluating a porous earth formation. The method may include estimating a value of at least one parameter of interest of the earth formation using a signal indicative of acoustic waves generated at a metallic surface (200) in communication with the earth formation when the metallic surface (200) is exposed to a constant magnetic field (250) normal to the metallic surface (200) and a harmonic magnetic field (260) along the metallic surface. The signal may be generated by a sensor responsive to the acoustic waves. The apparatus may include a first magnetic source (230) configured to generate a constant magnetic field (250), a second magnetic source (240) configured to generate a harmonic magnetic field (260), and a sensor (220) configured to generate a signal in response to acoustic waves.