Method For Guiding A Downhole Tool Assembly Using An Above-Ground Receiver System

• US 20130293233A1
• Filed: 07/08/2013
• Published: 11/07/2013
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Charles Machine Works Inc (Toro)
• Original Assignee: Charles Machine Works Inc (Toro)
• Inventors: Cole, Scott Bryan
• Granted Patent: US 9,146,286 B2
• Time in Patent Office: Days
• US Class Current: 324/344
• CPC Class Codes: E21B 47/0232 at least one of the energy sources or one of the detectors being located on or above the ground surface
• CPC Class Codes: G01R 33/02 Measuring direction or magnitude of magnetic fields or magnetic flux G01R33/20 takes precedence
• CPC Class Codes: G01V 3/15 specially adapted for use during transport, e.g. by a person, vehicle or boat
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves

Abstract

A method and receiver system for identifying a location of a magnetic field source using two horizontally displaced tri-axial antennas. In a preferred embodiment two tri-axial antennas are positioned at opposite ends of a receiver frame. Each antenna detects in three dimensions a magnetic field from a source or transmitter. The receiver is maintained in a horizontal plane and the receiver is moved in the horizontal plane until a flux angle measured at each of the two points is zero so that the receiver is in the vertical plane perpendicular to the axis of the source. The depth and location of the source in three dimensions relative to the receiver is determined using the detected field values. The receiver is moved in a direction defined by a line containing the two points of the receiver until a magnitude of the magnetic field detected at each of the two points is substantially the same so that the receiver is positioned above the source.

Claims

1. A receiver system for identifying a location of a magnetic field source, the receiver comprising:

a first triaxial antenna to detect a dipole magnetic field from the magnetic field source in three dimensions;

a second triaxial antenna to detect the dipole magnetic field from the magnetic field source in three dimensions simultaneously with the first triaxial antenna; and

a processor to receive an antenna signal from each of the first triaxial antenna and the second triaxial antenna and to determine the location of the magnetic field source using the antenna signals;

wherein the first triaxial antenna and the second triaxial antenna are laterally displaced from each other a distance.

2. The receiver system of claim 1 further comprising an orientation sensor to detect an orientation of the first triaxial antenna and the second triaxial antenna.

3. The receiver system of claim 2 wherein the processor uses the orientation of the first and second triaxial antennas to determine the location of the magnetic field source.

4. The receiver system of claim 1 wherein the first triaxial antenna comprises:

a first winding defining an aperture area;

a second winding defining an aperture area; and

a third winding defining an aperture area.

5. The receiver system of claim 4 wherein the aperture area of each winding is the same and the windings have a common center point.

6. The receiver system of claim 1 wherein the first triaxial antenna is laterally displaced from the second triaxial antenna in substantially the same horizontal plane and a known distance.

7. The receiver system of claim 1 wherein the first triaxial antenna and the second biaxial antenna are maintained in a substantially horizontal plane.

8. A receiver system for identifying a location of a magnetic field source, the receiver comprising:

two triaxial antennas to detect a magnetic field from a source; and

a processor adapted to receive an antenna signal from each of the two triaxial antennas and to determine a location of the source using the antenna signals;

wherein the two triaxial antennas detect the magnetic field when the antennas are held in a substantially horizontal plane.

9. The receiver system of claim 8 further comprising a frame to support at least one of the two triaxial antennas, wherein the location of the source is determined relative to the frame.

10. The receiver system of claim 9 further comprising supporting the processor on the frame.

11. The receiver system of claim 8 wherein at least one of the two triaxial antennas comprises:

a first winding defining an aperture area;

a second winding defining an aperture area; and

a third winding defining an aperture area.

12. The receiver system of claim 8 wherein the two triaxial antennas are maintained in substantially the same horizontal plane.

13. The receiver system of claim 8 further comprising a radio antenna to transmit information from the receiver to a remote unit.

14. The receiver system of claim 13 wherein information transmitted to the remote unit comprises the location of the source.

15. The receiver system of claim 13 wherein the remote unit comprises a drilling machine.

16. A method for tracking a below ground source of a magnetic field, the method comprising:

maintaining a first triaxial antenna and a second triaxial antenna in a substantially horizontal plane;

simultaneously detecting in three dimensions a magnetic field from a source both the first triaxial antenna and the second triaxial antenna;

moving one or both of the first and second triaxial antennas in the substantially horizontal plane until a flux angle measured at each of the first and second triaxial antennas is zero; and

calculating a location of the source in three dimensions using the detected magnetic fields.

17. The method of claim 16 further comprising providing a frame to support at least the first triaxial antenna and a processor used to calculate the location of the source in three dimensions.

18. The method of claim 17 further comprising transmitting information wirelessly from the frame to a remote location.

19. The method of claim 18 further comprising displaying the location of the source at both the frame and the remote location.

20. The method of claim 16 further comprising determining an orientation of the source and using both the orientation and the detected magnetic fields to calculate the location of the source.