Radio frequency resistivity and dielectric constant well logging utilizing phase shift measurement

摘要

The invention disclosed herein includes methods and apparatus for determining the resistivity and dielectric constant of earth materials in the vicinity of a well borehole. A radio frequency electromagnetic field in the frequency range from 20 to 40 megahertz is generated in a borehole and the total electromagnetic field at two longitudinally spaced locations is detected. Measurements of the relative phase shift in the field between the detector locations and the amplitude of the field at least at one of the detector locations may then be interpreted according to predetermined relationships in terms of the earth formation resistivity and dielectric constant.