Well logging tool and method for determining resistivity by using phase difference and/or attenuation measurements

摘要

An apparatus and method for determining resistivity of a formation surrounding a borehole comprises a housing, at least first and second transmitting antennas affixed to the housing for transmitting electromagnetic waves to the formation, and at least first and second receiving antennas for detecting the electromagnetic waves. The first receiving antenna is affixed to the housing at a position longitudinally located above the first and second transmitting antennas, and the second receiving antenna is longitudinally located below the first and second transmitting antennas. The measurements needed to calculate the resistivity of the formation may be determined while drilling the borehole.