Abstract: 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.

Abstract: An exemplary embodiment of the invention includes method for measuring the dielectric constant and resistivity of the invaded zone and the virgin formation in a fluid filled well bore hole. Dual induction laterolog measurements are employed to determined R.sub.t and R.sub.xo. Dual spaced radio frequency dielectric induction log measurements are employed to determine .epsilon..sub.t and .epsilon..sub.xo. By combining these measurements, a movable oil plot may be obtained in highly resistive formations.

Abstract: An odometer that employs a pulse generator, the pulses of which correspond to a given increment of linear distance. It has a correction circuit which may be set to either add or subtract a pulse after a predetermined number of pulses have been counted. This corrects the linear distance measured for any cumulated total. Consequently, inaccuracies in the dimension represented by each pulse will be periodically compensated for by the added or deleted pulse.