BORING TOOL TRACKING/GUIDING SYSTEM AND METHOD WITH UNCONSTRAINED TARGET LOCATION GEOMETRY

• US 20050083060A1
• Filed: 10/22/2004
• Published: 04/21/2005
• 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 6,917,202 B2
• Time in Patent Office: Days
• US Class Current: 324/326
• 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 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 orientation of the boring tool, a method comprising the steps of

accepting a target position to which the boring tool is to be guided including a target pitch orientation and a target roll orientation;

measuring the locating signal at a receiving position as well as the pitch and yaw orientations of the boring tool; and

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, measured pitch and yaw orientations of the boring tool, the target pitch orientation and the target yaw orientation.

2. The method of claim 1 wherein the target position is at least laterally offset with respect to the receiving position.

3. The method of claim 1 wherein said boring tool includes a magnetometer and wherein the step of measuring the pitch and yaw orientations of the boring tool uses readings taken from said magnetometer.

4. The method of claim 1 wherein the step of generating steering commands generates a horizontal steering command and a vertical steering command in a mathematically coupled manner.

5. The method of claim 4 wherein the step of generating steering commands, at least in part, uses the expression:

$\mathrm{\delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>Y=-\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\beta <br><br>}}_T+\frac{b_{y_T}}{b_{x_T}}$

to laterally guide the boring tool to the target position where x and y are orthogonal coordinate axes forming part of a global coordinate system having a global coordinate system origin centered on the boring tool, coinciding with an origin of the dipole locating signal, to define a horizontal plane, δ

Y represents a flux slope in the horizontal plane normal to the global x axis sharing the global coordinate origin, β

_T represents the target yaw orientation of the boring tool for arrival at the target position, b_yT is a flux at the target position taken along the y coordinate axis determined using measurements at the receiving position and b_xT is another flux at the target position taken along the x coordinate axis determined using measurements at the receiving position.

6. The method of claim 5 wherein the step of generating steering commands includes the step of directing steering in one lateral direction when δ

Y is positive in sign and directing steering in an opposing lateral direction when δ

Y is negative in sign.

7. The method of claim 4 wherein the step of generating steering commands, at least in part, uses the expression:

$\mathrm{\delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>Z=\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\varphi <br><br>}}_T-\frac{b_{z_T}}{b_{x_T}}$

to vertically guide the boring tool to the target position where z is a vertical, orthogonal coordinate axis in the global coordinate system sharing said global coordinate system origin, δ

Z represents a flux slope in a vertical plane defined by the global x and z axes, Φ

T represents a target pitch of the boring tool for arrival at the target position and b_zT is a flux at the target position taken along the z coordinate axis determined using measurements at the receiving position and b_xT is another flux at the target position taken along the x coordinate axis determined using measurements at the receiving position.

8. The method of claim 7 wherein the step of generating steering commands includes the step of directing steering in one vertical direction when δ

Z is positive in sign and directing steering in an opposing vertical direction when δ

Z is negative in sign.

9. 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, an assembly comprising:

means for accepting a target location to which the boring tool is to be guided including a target pitch orientation and a target roll orientation;

receiving means for measuring the locating signal at a receiving position; and

processing means 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 receiving means, measurements of the pitch and yaw orientations of the boring tool, the target pitch orientation and the target yaw orientation.

10. The assembly of claim 9 wherein said processing means is configured for generating the steering commands with the target position at least laterally offset with respect to the receiving position.

11. The assembly of claim 9 wherein said boring tool includes a magnetometer at least for measuring the pitch and yaw orientations of the boring tool.

12. The assembly of claim 9 wherein said processing means generates the steering commands by producing a horizontal steering command and a vertical steering command in a mathematically coupled manner.

13. The assembly of claim 12 wherein said processing means for generating steering commands, at least in part, uses the expression:

$\mathrm{\delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>Y=-\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\beta <br><br>}}_T+\frac{b_{y_T}}{b_{x_T}}$

to laterally guide the boring tool to the target position where x and y are orthogonal coordinate axes forming part of a global coordinate system having a global coordinate system origin centered on the boring tool, coinciding with an origin of the dipole locating signal, to define a horizontal plane, δ

Y represents a flux slope in the horizontal plane normal to the global x axis sharing the global coordinate origin, β

_T represents the target yaw orientation of the boring tool for arrival at the target position, b_yT is a flux at the target position taken along the y coordinate axis determined using measurements at the receiving position and b_xT is another flux at the target position taken along the x coordinate axis determined using measurements at the receiving position.

14. The assembly of claim 13 wherein said processing means directs steering in one lateral direction when δ

Y is positive in sign and directs steering in an opposing lateral direction when δ

Y is negative in sign.

15. The assembly of claim 12 wherein said processing means generates at least one steering command using the expression:

$\mathrm{\delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>Z=\tan <br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\varphi <br><br>}}_T-\frac{b_{z_T}}{b_{x_T}}$

to vertically guide the boring tool to the target position where z is a vertical, orthogonal coordinate axis in the global coordinate system sharing said global coordinate system origin, δ

Z represents a flux slope in a vertical plane defined by the global x and z axes, Φ

_T represents a target pitch of the boring tool for arrival at the target position and b_zT is a flux at the target position taken along the z coordinate axis determined using measurements at the receiving position and b_xT is another flux at the target position taken along the x coordinate axis determined using measurements at the receiving position.

16. The assembly of claim 15 wherein said processing means generates at least one steering command directing steering in one vertical direction when δ

Z is positive in sign and directing steering in an opposing vertical direction when δ

Z is negative in sign.