Radar plow drillstring steering

• US 20030107511A1
• Filed: 11/04/2002
• Published: 06/12/2003
• Est. Priority Date: 03/28/2001
• Status: Active Grant

• Current Assignee: Gerald L. Stolarczyk, Larry G. Stolarczyk
• Original Assignee: Gerald L. Stolarczyk, Larry G. Stolarczyk
• Inventors: Stolarczyk, Larry G., Stolarczyk, Gerald L.
• Granted Patent: US 6,633,252 B2
• Time in Patent Office: Days
• US Class Current: 342/22
• CPC Class Codes: F41H 11/12 Means for clearing land minefields; Systems specially adapted for detection of landmines
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves

Abstract

A radar-plow drillstring steering system comprises a steering plow and a measurements-while-drilling instrument for mounting just behind the drill bit and downhole motor of a drill rod. The instrument includes a radar system connected to upward-looking and downward-looking horn antennas and a dielectric-constant sensor. The steering plow includes four pressure pads radially distributed around the outside surface and their associated servo motors. A coordinated control of the pressure pads allows the steering plow to push the drillstring and drill bit up-down-left-right. The antennas and sensor are embedded in respective ones of the pressure pads and are used to electronically and non-invasively probe a coal seam to locate its upper and lower boundary layers. The dielectric-constant sensor provides corrective data for the up and down distance measurements. Such measurements and data are radio communicated to the surface for tomographic processing and user display. The radio communication uses the drillstring as a transmission line and F1/F2 repeaters can be placed along very long runs to maintain good instrument-to-surface communication. A docking mechanism associated with the instrument and its antenna array allows the instrument to be retrieved back inside the drillstring with a tether should the drill head become hopelessly jammed or locked into the earth.

Claims

1. A plow steering system for directional drilling, comprising:

a set of first through fourth pressure pads distributed around the outside surface of a steering plow for placement behind a directional drilling drill bit;

an upward-looking radar antenna embedded in said first pressure pad;

a downward-looking radar antenna embedded in said second pressure pad;

a ground-penetrating radar transceiver connected to each of the upward-looking and downward-looking radar antennas, and providing for return signal attenuation and phase shift measurements, and for providing from said measurements real-time estimates of the distances transmitted radar signals traveled before being reflected back to a respective antenna; and

a guidance control providing for steering of said directional drilling drill bit according to said real-time estimates, wherein said steering is provided by retracting and extending individual ones of said first through fourth pressure pads.

2. The system of claim 1, further comprising:

a dielectric-constant sensor embedded in either of said third and fourth pressure pads, and providing corrective data to said real-time estimates of the distances provided by the ground-penetrating radar transceiver.

3. The system of claim 1, further comprising:

a docking mechanism for remote disconnection of the ground-penetrating radar transceiver from said directional-drilling drillstring; and

a tether for causing the docking mechanism to release the ground-penetrating radar transceiver and allowing it to be withdrawn from within the length of said drillstring.

4. The system of claim 1, further comprising:

a docking mechanism for remote automatic connection of the ground-penetrating radar transceiver to said directional-drilling drillstring with the aid of hydraulic pumping to shuttle it to a distal end.

5. The system of claim 1, further comprising:

a user display for providing tomographic images of a coal bed to an operator from data provided by the ground-penetrating radar transceiver.

6. The system of claim 5, further comprising:

a signal repeater located along said drillstring between the user display and the ground-penetrating radar transceiver and providing for extended communication between them.

7. The system of claim 1, further comprising:

a navigation processor connected to sense the course taken by said directional-drilling drillstring and for providing information to the guidance control.

8. The system of claim 1, further comprising:

a hydroelectric generator for receiving a hydraulic flow through said drillstring and for powering the ground-penetrating radar transceiver.

9. The system of claim 8, further comprising:

a magnetic clutch for coupling-in mechanical power to the hydroelectric generator collocated with the ground-penetrating radar transceiver inside an explosion-proof enclosure.

10. The system of claim 1, further comprising:

an inductive coupler for supporting a radio communication along said drillstring acting as a transmission line.