Apparatus and methods of controlling recordation of resistivity-related readings in determining formation resistivity

摘要

In various embodiments, apparatus and methods are provided to determine formation resistivity associated with a well. Measurements taken using sub-arrays of a tool at different distances of investigation can be used to determine formation resistivity, where the sub-arrays are arranged to make azimuthal related measurements. Separations readings related to resistivity can be generated from signals received from different directions and can be analyzed to characterize validity of a measurement reading. Additional apparatus, systems, and methods are disclosed.

主权项

1. A method comprising:
generating a probe signal from a sub-array of a plurality of sub-arrays of a tool and receiving, in the sub-array, a signal from a first direction and a signal from a second direction in response to generating the probe signal, the sub-arrays of the tool arranged to make azimuthal related measurements with respect to a borehole; comparing a first resistivity-related reading from the signal from the first direction to a second resistivity-related reading from the signal from the second direction to provide a separation reading; comparing the separation reading to a threshold level; and recording a resistivity-related reading as a valid measure to determine formation resistivity from the comparison of the separation reading to the threshold level when the separation reading is less than or equal to the threshold level.