Boring tool tracking/guiding system and method with unconstrained target location geometry

• US 20060238201A1
• Filed: 06/13/2006
• Published: 10/26/2006
• Est. Priority Date: 11/20/2001
• Status: Active Grant

• Current Assignee: Merlin Technologies Incorporated
• Original Assignee: Merlin Technologies Incorporated
• Inventors: Mercer, John E., Brune, Guenter W., Chau, Albert W.
• Granted Patent: US 7,218,116 B2
• Time in Patent Office: Days
• US Class Current: 324/338
• CPC Class Codes: E21B 47/024 of devices in the borehole determining slope or direction of the borehole E21B47/022
• CPC Class Codes: E21B 7/04 Directional drilling
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12
• 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

Abstract

Tracking a boring tool is performed within an underground region using a locating signal. The boring tool is moved through the ground during a series of distance movements such that potential movement of the boring tool during any one of the distance movements is less than a maximum movement value. A current positional relationship is determined for a current one of the distance movements based on: a last-determined positional relationship established for an immediately preceding one of the distance movements, certain orientation parameters, the maximum movement value and the determined signal strength of the locating signal in the current positional relationship. Target coordinates are accepted and a target position, based on the target coordinates, is included as part of the current positional relationship. The position of the target is unconstrained with respect to system geometry. Steering command features are provided along with steering warnings.

Claims

1. In a system for tracking a boring tool within an underground region using a portable locator, in which system the boring tool is configured for transmitting a dipole locating signal and where the position of the boring tool is characterized, at least in part, by certain orientation parameters which are transmitted from the boring tool, a method comprising:

from a first position, moving the boring tool to a second position during a time interval, said first position forming part of a first positional relationship relative to the portable locator at a locator position;

with the boring tool at the second position, measuring a signal strength of the locating signal with the portable locator and receiving said certain orientation parameters from the boring tool with the portable locator;

establishing a maximum movement value for the boring tool such that any potential movement of the boring tool over the time interval is less than the maximum movement value and saving the maximum movement value in the portable locator; and

based on the first positional relationship, said certain orientation parameters, the maximum movement value and the determined signal strength of the locating signal as received by the portable locator with the boring tool at the second position, configuring the portable locator for determining a second positional relationship including the boring tool at the second position relative to the portable locator at the locator position.

2. The method of claim 1 wherein said certain orientation parameters include yaw of the boring tool in said region.

3. The method of claim 1 wherein said certain orientation parameters include pitch of the boring tool in said region.

4. The method of claim 1 wherein the boring tool defines an elongation axis and said method includes determining a first lateral distance, as part of the first positional relationship, measured along the elongation axis from the boring tool to an orthogonal plane defined as (i) including the locator position and (ii) intersecting the elongation axis normal thereto.

5. The method of claim 4 wherein said locator is configured for determining the second positional relationship, at least in part, by comparing the first lateral distance to the maximum movement value.

6. The method of claim 5 wherein comparing establishes that the first lateral distance is more than said maximum movement value and the first positional relationship further establishes that the locator position is ahead of the boring tool with respect to said orthogonal plane.

7. The method of claim 6 wherein the second positional relationship is determined, at least in part, using an angle α

defined between the elongation axis of the boring tool and a line extending from the boring tool to the portable locator at the locator position, said method including determining α

using the expression;

$\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\alpha <br><br>}=\frac{\left(-3<br><br>b_{\mathrm{\xi <br><br>}}+\sqrt{9<br><br>b_{\mathrm{\xi <br><br>}}^2+8<br><br>b_{\mathrm{\zeta <br><br>}}^2}\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\sin <br><br>\text{\hspace{1em}<br><br>}<br><br>\left(b_{\mathrm{\zeta <br><br>}}\right)}{2<br><br><br><br>b_{\mathrm{\zeta <br><br>}}<br><br>}$

where an orthogonal pair of axes ξ and

ζ

define an axial plane including the elongation axis of the boring tool and including the locator position such that ξ

is coincident with the elongation axis of the boring tool and ζ

is normal thereto in said axial plane and where b_ξ

and b_ζ

are components of the dipole locating field along the ξ and

ζ

axes, respectively.

8. The method of claim 6 wherein the second positional relationship is determined, at least in part, based on a radial distance, r, between the second position of the boring tool and the locator position established using the expression:

$\frac{1}{r^3}=-\frac{1}{4}<br><br>b_{\mathrm{\xi <br><br>}}+\sqrt{\frac{9}{16}<br><br>b_{\mathrm{\xi <br><br>}}^2+\frac{1}{2}<br><br>b_{\mathrm{\zeta <br><br>}}^2}$

where an orthogonal pair of axes ξ and

ζ

define an axial plane including the elongation axis of the boring tool and the locator position such that ξ

is coincident with the elongation axis of the boring tool and ζ

is normal thereto in said axial plane and where b_ξ

and b_ζ

are components of the dipole locating field along the ξ and

ζ

axes, respectively.

9. The method of claim 5 wherein comparing establishes that the first lateral distance is less than said maximum movement value and that the locator position is ahead of the boring tool, in the first positional relationship, when projected orthogonally onto the elongation axis of the boring tool.

10. In a system for tracking a boring tool within an underground region, in which system the boring tool is configured for transmitting a dipole locating signal and where the position of the boring tool is characterized, at least in part, by certain orientation parameters which are transmitted from the boring tool, a locator comprising:

a receiver for measuring a signal strength of the locating signal at a receiving position and for receiving said certain orientation parameters of the boring tool after moving the boring tool during a time interval from a first position, forming part of a first positional relationship relative to the receiving position, to a second position, where the boring tool is subject to a maximum movement value such that any potential movement of the boring tool over the time interval is less than the maximum movement value; and

a processor for determining a second positional relationship of the boring tool at the second position relative to the receiving position based on the first positional relationship, said certain orientation parameters, the maximum movement value and the determined signal strength of the locating signal at the second position.

11. The locator of claim 10 wherein said processor is configured for using yaw of the boring tool as one of said certain orientation parameters.

12. The locator of claim 10 wherein said processor is configured for using pitch of the boring tool as one of said certain orientation parameters.

13. The locator of claim 10 wherein the boring tool defines an elongation axis and said processor is configured for using a first lateral distance determined as part of the first positional relationship and measured along the elongation axis from the boring tool to an orthogonal plane defined as (i) including the receiving position and (ii) intersecting the elongation axis normal thereto.

14. The locator of claim 13 wherein said processor determines the second positional relationship, at least in part, by comparing the first lateral distance to the maximum movement value.

15. The locator of claim 13 wherein said processor is configured for establishing when the first lateral distance is more than said maximum movement value where the first positional relationship places the receiving position ahead of the boring tool with respect to said orthogonal plane.

16. The locator of claim 15 wherein said processor is configured for determining the second positional relationship, at least in part, using an angle α

defined between the elongation axis of the boring tool and a line extending from the boring tool to the locator using the angle α

defined by the expression;

$\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\alpha <br><br>}=\frac{\left(-3<br><br>b_{\mathrm{\xi <br><br>}}+\sqrt{9<br><br>b_{\mathrm{\xi <br><br>}}^2+8<br><br>b_{\mathrm{\zeta <br><br>}}^2}\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\sin <br><br>\text{\hspace{1em}<br><br>}<br><br>\left(b_{\mathrm{\zeta <br><br>}}\right)}{2<br><br><br><br>b_{\mathrm{\zeta <br><br>}}<br><br>}$

where an orthogonal pair of axes ξ and

ζ

define an axial plane including the elongation axis of the boring tool and including the receiving position such that ξ

is coincident with the elongation axis of the boring tool and ζ

is normal thereto in said axial plane and where b_ξ

and b_ζ

are components of the dipole locating field along the ξ and

ζ

axes, respectively.

17. The locator of claim 15 wherein said processor is configured for determining the second positional relationship based, at least in part, on a radial distance, r, between the second position of the boring tool and the receiving position using the expression:

$\frac{1}{r^3}=-\frac{1}{4}<br><br>b_{\mathrm{\xi <br><br>}}+\sqrt{\frac{9}{16}<br><br>b_{\mathrm{\xi <br><br>}}^2+\frac{1}{2}<br><br>b_{\mathrm{\zeta <br><br>}}^2}$

where an orthogonal pair of axes ξ and

ζ

define an axial plane including the elongation axis of the boring tool and the receiving position such that ξ

is coincident with the elongation axis of the boring tool and ζ

is normal thereto in said axial plane and where b_ξ

and b_ζ

are components of the dipole locating field along the ξ and

ζ

axes, respectively.

18. The locator of claim 14 wherein said processor is configured for establishing when the first lateral distance is less than said maximum movement value and where the first positional relationship places the receiving position ahead of the boring tool, when projected orthogonally onto the elongation axis of the boring tool.

19. The locator of claim 18 where an axial plane is defined by the elongation axis of the boring tool and including the receiving position and processor monitors one or more flux components of the dipole locating signal in said axial plane in a way which identifies the boring tool having passed the receiving position with respect to an orthogonal line extending through the receiving position orthogonal to the elongation axis of the boring tool as a part of the second positional relationship.

20. In a system for tracking a boring tool that is configured for transmitting a dipole locating signal within an underground region where movement of the boring tool is characterized by certain orientation parameters including pitch and yaw and which system is configured at least for establishing the pitch and yaw orientations of the boring tool, a locator comprising:

a user input that is configured for accepting a target location to which the boring tool is to be guided including a target pitch orientation and a target roll orientation;

a receiver for measuring the locating signal at a receiving position of the locator; and

a processor that is configured for generating steering commands for use in guiding the boring tool to the target location using measured values of the locating signal taken at the receiving position by said receiver, measurements of the pitch and yaw orientations of the boring tool, the target pitch orientation and the target yaw orientation.