High frequency dielectric induction well logging - determines phase shift between signals from receivers spaced above transmitter

摘要

A high-frequency electromagnetic field is produced by a probe in a well at 20-65 MHz. The total electromagnetic field is determined at a certain distance above the transmitter and a first signal is transmitted to the surface. This is repeated at a still higher location and the second signal produced from it is compared regarding phase shift in an electronic measuring and display station. This system can be used to determine simultaneously the conductivity and the dielectric constants of the soil formations around a well. This results in a clear distinction between formations impregnated with fresh water and those impregnated with mineral oil.