Logging tool employing a monopole current injection electrode for microresistivity imaging
AssigneeSchlumberger Technology Corporation
InventorTsili Wang
Life of this patent
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Abstract
A microresistivity logging tool includes a monopole current injection electrode and first and second potential electrodes deployed on a downhole tool body. A controller is configured to apply a high frequency alternating current between the monopole current injection electrode and a return and measure a corresponding AC potential difference between the first and second electrodes.
Claims16
A downhole microresistivity logging tool comprising:
- a logging tool body;
- a monopole current injection electrode configured to inject electrical current into a formation;
- a return electrode, the return electrode providing a return path for the electrical current injected by the monopole current injection electrode, the return electrode deployed in the tool body and spaced apart from the monopole current injection electrode;
- first and second spaced potential electrodes;
- and
- a controller configured to (i) apply a high frequency alternating current between the monopole current injection electrode and the fail return electrode and (ii) measure a corresponding AC potential difference between the first and second potential electrodes.
The logging tool of claim further comprising first and second return electrodes, the first and second return electrodes providing corresponding first and second return paths for the electrical current injected by the monopole current injection electrode, the monopole current injection electrode deployed axially between the first and second return electrodes.
A logging while drilling microresistivity tool comprising:
- a logging while drilling tool body a monopole current injection electrode configured to inject electrical current into a formation;
- first and second return electrodes configured to provide a corresponding first and second return paths the electrical current injected by the monopole current injection electrode, the first and second return electrodes deployed in the tool body and spaced apart from the monopole current injection electrode, the current injection electrode deployed axially between the first and second return electrodes;
- first and second spaced potential electrodes;
- and
- a controller configured to (i) apply a high frequency alternating current between the monopole current injection electrode and the return electrode and (ii) measure a corresponding AC potential difference between the first and second electrodes.
Dependencies are inferred from the claim text.