Measurements of electrical properties through non magneticially permeable metals using directed magnetic beams and magnetic lenses

• US 6,630,831 B2
• Filed: 09/04/2001
• Issued: 10/07/2003
• Est. Priority Date: 09/02/2000
• Status: Expired due to Fees

• Current Assignee: Em-Tech Company Limited
• Original Assignee: Em-Tech Company Limited
• Inventors: Amini, Bijan K.
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): LE, TOAN M
• Application Number:
  US09/946,692
• Publication Number:
  US 20020105333A1
• Time in Patent Office: 763 Days
• Field of Search: 324/339, 324/341, 343/787
• US Class Current: 324/339
• CPC Class Codes: G01V 3/28 using induction coils

Abstract

The invention subject of this specification utilizes the technique of inductive magnetic coupling of Electromagnetic waves to EM barrier materials in combination with transmission of Electromagnetic waves through non-permeable material to facilitate the measurement of resistivity of geologic formation beyond the well casing.

Claims

1. The method of focusing or lensing an oscillating magnetic flux to measure the electrical resistivity of media within a geologic formation surrounding a cased well bore comprising the steps of:

(1) generating at least one magnetic flux proximate to a non-magnetically permeable section of a casing;

(2) oscillating the magnetic flux at least at one frequency suitable to pass through the segment of the well casing for entering a surrounding geological formation such that the flux engages with electrically conductive media contained within the surrounding formation to create eddy currents within the media;

(3) inducing a separate oscillating magnetic flux created by the eddy currents in the electrically conductive media within the formation such that a field of the induced magnetic flux extends back to the well casing;

(4) receiving, from within the casing, the induced magnetic flux of the geologic formation;

(5) converting the induced flux into electrical signals that are filtered and processed;

(6) determining the electrical resistivity of the media located in the geologic formation proximate to the well casing based on the electrical signals; and

(7) determining the characteristics of the media located in the geologic formation proximate to the well casing by evaluating the electrical resistivity.

2. A method of measuring the resistivity within an underground geologic formation through a well casing comprising the steps of:

a. generating an oscillating magnetic flux;

b. transmitting the magnetic flux through a portion of the well casing comprised of a non-magnetically permeable material;

c. engaging the magnetic flux with electrically conductive media within the formation to induce eddy currents;

d. receiving resulting magnetic flux induced by the eddy currents within the media through a non-magnetically permeable portion of the well casing; and

e. measuring the received magnetic flux to evaluate the resistivity of the media.

3. The method of claim 2 wherein the resulting magnetic flux induced by the eddy currents is received through at least one separate portion of the well casing.

4. The method of claim 2 wherein oscillating magnetic flux of a plurality of frequencies is transmitted.

5. The method of claim 2 wherein the oscillating magnetic flux is first transmitted through near practical saturated magnetically permeable material.

6. The method of claim 2 further comprising nulling the transmitter device from the flux receiving means.

7. The method of claim 2 further comprising moving the transmitting device in relation to the non-magnetically permeable well casing material.

8. An apparatus for transmitting and receiving oscillating magnetic flux through a well casing comprising:

a. a power supply;

b. a portion of well casing constructed of non-magnetically permeable material;

c. at least one oscillating magnetic flux transmitter device located proximate to a portion of non-magnetically permeable casing;

d. at least one receiver device nulled to the transmitting device and located proximate to a non-magnetically permeable portion of the well casing; and

e. means to process received magnetic flux into electronic signals.

9. The apparatus of claim 8 further comprising a magnetically permeable component constructed of stainless steel.

10. The apparatus of claim 8 wherein at least one transmitter or receiver is located within a non-magnetically permeable portion of a casing connector collar.

11. The apparatus of claim 8 comprising a plurality of transmitters substantially oriented in at least one plane orthogonal to the axis of the casing.

12. The apparatus of claim 8 wherein the transmitter is oriented in substantially 360 degrees around the circumference of the casing.

13. The apparatus of claim 8 comprising a transmitter component that can be moved along the axial direction within the annulus of a well casing.

14. The apparatus of claim 9 wherein a magnetically permeable component is, near practical saturated.

15. The apparatus of claim 14 wherein the magnetically permeable component is a culminator.

16. The apparatus of claiml5 wherein a receiver means is proximate to the culminator.

17. An apparatus for transmitting and receiving oscillating magnetic flux through a well casing comprising:

a. a power supply;

b. at least one oscillating magnetic flux transmitter device and a magnetic flux receiver located proximate to a non-magnetically permeable portion of a well casing;

c. means to process received magnetic flux into electrical signals; and

d;

means to transmit the electrical signals to a monitoring device.