| 摘要 |
Detecting in an earth formation a boundary between first and second formation regions having different resistivities, wherein the first formation region is traversed by a wellbore, using a logging tool provided with a number of electrodes including a monitoring electrode, the method having:a) selecting a location of the logging tool in the wellbore;b) assuming a position of the boundary relative to the selected location, selecting outside the wellbore a target point relative to the selected location, and selecting a target value for a selected parameter in the target point;c) assuming a model wherein the logging tool in the wellbore is surrounded by a homogeneous formation having the resistivity of the first formation region, and determining how two of the electrodes have to be energized in order that in the target point the selected parameter has the target value;d) selecting a monitoring parameter at the monitoring electrode;e) placing the logging tool at the selected location in the wellbore;f) determining a detection value of the monitoring parameter resulting from energizing the two electrodes as determined in step c); and,g) interpreting the detection value of the monitoring parameter in order to detect the boundary.
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