1. n. [Formation Evaluation]
A measurement of the formation resistivity made on drillpipe at a frequency in the range of 100 kHz to 10 GHz, most commonly 2 MHz. The basic measurement is accomplished using a transmitter and two receivers. At these frequencies, the response is best explained as the propagation of a wave. Thus, the phase shift and attenuation of the wave between the receivers are measured and transformed to give the phase shift and the attenuation resistivity. In practice, multiple transmitters may be used to obtain different depths of investigation and achieve borehole compensation. The wavelength is such that the borehole has a minor effect, but one for which correction may be needed.
See: attenuation resistivity, dielectric resistivity, horizontal resistivity, phase shift, phase-shift resistivity, polarization horn, propagation resistivity, relative dielectric permittivity, resistivity log, vertical resistivity