Texaco Inc.

Larry L Adams

Larry Wayne Thompson

Percy T Cox

Richard A Meador

James A Fuchs

A system operating at radio frequencies in the range of 10 MHZ to 60 MHZ is provided for simultaneously determining the resistivity and dielectric constant of earth formations in the vicinity of a well bore. A transmitter coil and two longitudinally spaced receiver coils are provided in the system. Circuit means for measuring the unnormalized amplitude ratio and the relative phase shift of electromagnetic waves at the spaced receiver coils are provided. A relationship is given whereby the formation dielectric constant and resistivity may be obtained from the amplitude ratio and relative phase shift measurements.

Electromagnetic wave logging system for determining resistivity and

The invention disclosed herein includes methods and apparatus for determining true formation resistivity, flushed zone resistivity and invasion diameter of the earth formation in the vicinity of a well borehole. A radio frequency electromagnetic field in the frequency range from 800 kilohertz to 4 megahertz is generated in a borehole and the electromagnetic field is detected at a plurality of longitudinally spaced locations. Measurements of the attenuation and propagation velocity of the electromagnetic wave at the longitudinally spaced receivers may then be interpreted according to predetermined relationships in terms of the formation resistivity, flushed zone resistivity and invasion diameter surrounding the borehole.

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Stafford, TX, United States of America

Larry L Adams