Electrode Tool Leakage Current Correction
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Solution Overview
Problem
Existing electrode-based tools in the oil and gas industry face inaccuracies in measuring electromagnetic formation properties due to assumptions of infinite internal impedance, which neglects leakage currents, leading to decreased accuracy in resistivity and dielectric property measurements.
Innovation Solution
The use of a predetermined internal impedance model or table to estimate leakage currents, allowing for correction of electrode-based tool measurements by accounting for these currents in the processing of data, particularly through the application of modified focusing equations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If assumptions of infinite internal impedance are made to simplify processing, then device complexity is reduced, but measurement precision deteriorates due to neglected leakage currents
Solution Approach 1:
The patent changes the impedance parameter from idealized infinite value to a realistic finite value characterized by internal impedance models or tables. This allows leakage currents to be calculated and accounted for, improving measurement precision while maintaining manageable processing complexity through the use of pre-characterized impedance data.
Solution Approach 2:
The patent uses measured or modeled internal impedance characteristics as a copy of the actual tool behavior to estimate leakage currents. By creating a digital representation of the tool's electrical characteristics, the system can correct measurements without requiring complex real-time modeling, thus balancing accuracy and processing simplicity.
2Ease of operation
If leakage currents are neglected to simplify measurements, then ease of operation is improved, but reliability deteriorates due to inaccurate resistivity and dielectric property measurements
Solution Approach 1:
The patent performs preliminary characterization of internal impedance and creates lookup tables or models before actual formation measurements are taken. This preliminary action captures the tool's electrical characteristics, allowing leakage current corrections to be applied automatically during operation without adding complexity to the measurement process itself, thus maintaining ease of operation while improving reliability.
3Manufacturing precision
If internal impedance is characterized through testing to create models or tables, then manufacturing precision is improved, but loss of time increases due to additional characterization steps
Solution Approach 1:
The patent performs internal impedance characterization and model creation as a preliminary action during tool manufacturing or calibration, rather than during field operations. By completing this time-consuming characterization work beforehand and storing results in lookup tables or simplified models, the system achieves high manufacturing precision while minimizing time loss during actual logging operations.
Solution Approach 2:
The patent creates simplified digital copies (models or lookup tables) of the complete internal impedance characteristics. These copies capture the essential behavior of the tool's electrical properties without requiring the full complexity of the original characterization data during operations, thus reducing processing time while maintaining accuracy.
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 significantly improves the accuracy of derived electromagnetic properties by accounting for leakage currents, reducing errors associated with neglecting them, and bringing the results closer to those of ideal tools.
Implementation Method 1
estimate leakage current between at least one of the plurality of current electrodes and the at least one return electrode based on the collected one or more voltage measurements and a predetermined internal impedance model or table
Data Source
AI summary
An example system includes an electrode-based tool for deployment in a downhole environment. The electrode-based tool has a plurality of current electrodes, at least one voltage monitoring electrode, at least one return electrode, and electronics to collect one or more voltage measurements from the at least one voltage monitoring electrode as current from at least one of the plurality of current electrodes is injected into the downhole environment and flows to the at least one return electrode. The system also includes at least one processor to estimate leakage current between at least one of the plurality of current electrodes and the at least one return electrode based on the collected one or more voltage measurements and a predetermined internal impedance model or table. The at least one processor is configured to derive a corrected downhole environment parameter based at least in part on the estimated leakage current.