| 摘要 |
<p>A method and apparatus are disclosed for identifying boundaries between thin beds having different resistivities. In one embodiment, the method includes (a) transmitting an oscillatory signal from a first transmitter; (b) determining a first phase difference between signals induced in two receivers by the oscillator signal from the first transmitter; (c) transmitting an oscillatory signal from a second transmitter; (d) determining a second phase difference between signals induced in the two receivers by the oscillatory signal from the second transmitter; and (e) calculating an interferometric difference between the first and second phase differences. When the transmitters are symmetrically located with respect to the receivers, the interferometric difference exhibits a maximum or minimum value near the boundary location. This low-complexity method provides good boundary detection results when the bed thickness is larger than the transmitter-receiver spacing. In a second method embodiment, the interferometric difference is calculated from the logarithm of the measured attenuation.</p> |
