Patent Number: 6,294,917

Title: Electromagnetic induction method and apparatus for the measurement of the electrical resistivity of geologic formations surrounding boreholes cased with a conductive liner

Abstract: Provided is a technique, including a method and a computer program product, to dynamically measure characteristics of geologic formations while hydrocarbons are being extracted therefrom. Specifically, the present invention allows measuring the resistivity of geologic formations in which a borehole has been formed therein and encased with a conductive casing, such as a conductive liner. This has been achieved by providing a method and computer program product that compensates for the effects of a conductive liner by measuring the characteristics of the geologic formation as a function of a ratio of two magnetic fields sensed by a receiver disposed in one of the boreholes.

Inventors: Nichols; Edward (Berkeley, CA)

Assignee: Electromagnetic Instruments, Inc.

International Classification: G01V 3/28 (20060101); G01V 3/18 (20060101); G01V 003/10 (); G01V 003/26 ()

Expiration Date: 09/25/2018