Abstract: A dipmeter in a well logging tool includes conventional type circuitry which senses the angle of inclination of the logging tool and an azimuth angle. The dipmeter also includes a non-conventional type bed detection sub-system. The bed detection sub-system includes at least three radio frequency oscillators having their coils mounted on pads of the logging tool. As the logging tool moves through the borehole, the electrical current passing through the coils on the pads causes lines of flux to circulate through the earth formation. Eddy currents are developed for each group of fluxlines created by a coil. As the earth formation changes, the eddy current changes accordingly causing a grid current in the oscillator to change. Portion of the grid currents are transmitted uphole and are recorded so that the interface between the types of earth's formation may be recorded with its relationship to the particular borehole and thus used to determine the dip of different earth formation beds.

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: Radio frequency electromagnetic fields are used to excite earth formations in the vicinity of a well borehole. The total field amplitude at a single coil receiver and at a dual coil receiver are detected and signals representative thereof are combined according to a predetermined relationship to obtain the relative permittivity and resistivity of the earth formations. By combining the measured permittivity with porosity measurements from another source according to predetermined relationships, the water saturation S.sub.w and residual oil saturation ROS may be determined and logged as a function of borehole depth.

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: A well logging system is provided which simultaneously employs a conventional deep induction log and a radio frequency dielectric log to differentiate similar high resistivity fresh water and oil prospective zones. A 16 megahertz radio frequency dielectric induction logging system which is responsive to both conductivity and permittivity of the earth derives a signal primarily related to both of these properties. A conventional 20 kilohertz deep induction system is used to derive a signal which is primarily a function of conductivity alone. When combined in accordance with predetermined relationships according to the invention the two measurements can be used to find oil prospective zones.