A standard calibration method based on a symmetric resistance network matrix for galvanic logging instruments

Area of Science:

• Geophysics
• Petroleum Engineering
• Electrical Logging

Background:

• High-resolution detection in complex formations necessitates advanced galvanic logging tools.
• Forward modeling is crucial for optimizing the design of these logging instruments.

Purpose of the Study:

• To develop a forward modeling method for galvanic multi-electrodes in complex formations.
• To enhance the accuracy of galvanic logging measurements through improved calibration.

Main Methods:

• Utilized a three-dimensional finite element numerical simulation to model galvanic multi-electrodes.
• Designed a symmetrical resistance network model with equivalent resistance between electrodes.
• Extended the asymmetrical admittance matrix to a symmetrical extended admittance matrix for calculation.

Main Results:

• Successfully established a forward model for galvanic logging in complex formations.
• The derived symmetrical resistance network model simplifies calculations.
• Verified improved measurement accuracy using a microcolumn-focused logging tool in simulated and actual oil wells.

Conclusions:

• The proposed calibration method significantly improves the measurement accuracy of galvanic logging instruments.
• The numerical simulation and resistance network approach provide a robust framework for tool design and analysis.
• This work contributes to more precise subsurface characterization in complex geological environments.