Bore location system

• US 7,151,376 B2
• Filed: 01/27/2006
• Issued: 12/19/2006
• Est. Priority Date: 09/08/2000
• Status: Expired due to Term

• Current Assignee: Merlin Technologies Incorporated
• Original Assignee: Merlin Technologies Incorporated
• Inventors: Mizuno, Morio
• Primary Examiner(s): Aurora, Reena
• Application Number:
  US11/341,789
• Publication Number:
  US 20060132136A1
• Time in Patent Office: 326 Days
• Field of Search: 324/326
• US Class Current: 324/326
• 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: E21B 7/046 horizontal drilling drilling with mechanical conveying means E21B7/003
• CPC Class Codes: G01V 3/081 the magnetic field is produced by the objects or geological structures characterised by the method of magnetic field measurement G01R33/00
• CPC Class Codes: G01V 3/15 specially adapted for use during transport, e.g. by a person, vehicle or boat

Abstract

A system and method for locating a horizontal bore below a ground surface includes a transmitting source configured to radiate from the bore a dipole magnetic field aligned with the bore. A receiver is located remote from the transmitting source and has a first coil and a second coil. Each coil defines an axis, wherein the axes of the first coil and the second coil are orthogonal to each other. A measurement device is in communication with the coils and configured to measure the phase of signals induced on the coils by the magnetic field when the axis of the first coil is horizontally perpendicular to the axis of the magnetic field and the axis of the second coil is vertically perpendicular to the axis of the magnetic field. The measurement device is also configured to determine the lateral position of the transmitting source relative to the coils responsively to the phase of the signals on the first coil and the second coil.

Claims

1. A system for locating a horizontal bore below a ground surface, said system comprising:

a transmitting source configured to radiate from said bore a dipole magnetic field aligned with said bore;

a receiver remote from said transmitting source and having a first coil and a second coil, each coil defining an axis, wherein said axes of said first coil and said second coil are orthogonal to each other; and

a measurement device in communication with said coils and configured to

measure the magnitude of signals induced on said coils by said magnetic field when said coils are disposed above said transmitting source, and

determine the yaw of said transmitting source relative to said axis of one of said coils responsively to said magnitudes of said signals on said first coil and said second coil.

2. A system for locating a horizontal bore below a ground surface, said system comprising:

a transmitting source configured to radiate from said bore a dipole magnetic field aligned with said bore;

a receiver remote from said transmitting source and having a first coil and a second coil, each coil defining an axis, wherein said axes of said first coil and said second coil are orthogonal to each other; and

a measurement device in communication with said coils and configured to

measure the magnitude of signals induced on said coils by said magnetic field when said coils are disposed above said transmitting source and said coils are vertically aligned with each other and above said transmitting source and when said axes of said first coil and said second coil are horizontal, and

determine the angular position of said transmitting source relative to said axis of one of said coils by determining an angle between said axis of said first coil and the axis of said transmitting source responsively to said magnitudes of said signals on said first coil and said second coil.

3. The system as in claim 2 wherein said measurement device is configured to determine the arctangent of said magnitude of said signal on second coil divided by said magnitude of said signal on said first coil.