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

  • US 4,012,689 A
  • Filed: 10/24/1974
  • Issued: 03/15/1977
  • Est. Priority Date: 10/24/1974
  • Status: Expired due to Term
First Claim
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1. A method for logging well boreholes to obtain measurements functionally related to the resistivity and dielectric constant of earth materials in the vicinity thereof, comprising the steps of:

  • generating in a well borehole at a first location a radio frequency electromagnetic field in the frequency range from 10 to 60 megahertz;

    detecting in the borehole at a second longitudinally spaced location from said first location the total electromagnetic field at said generated frequency and generating a first signal representative thereof;

    detecting in the borehole at a third location longitudinally spaced from said first and second locations the total electromagnetic field at said generated signal frequency and generating a second signal representative thereof;

    generating a third signal functionally related to the amplitude of the total electromagnetic field at least at one of said second or third locations as an indicator of the resistivity of the earth formations in the vicinity of the borehole;

    generating from said first and second representative signals an indication of the relative phase shift of the total electromagnetic field at said generated frequency between said second and third locations; and

    combining said phase shift indication and said third signal indicative of formation resistivity to derive an indication of the dielectric constant of the earth formations in the vicinity of the borehole.

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