Horizontal Directional Drilling Crossbore Detector

Patent metadata

Field	Value
Publication number	US-2016265347-A1
Application number	US-201615068793-A
Country	US
Kind code	A1
Filing date	Mar 14, 2016
Priority date	Mar 13, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

A crossbore detection system. The system is located in a downhole tool proximate a drill bit. The system comprises circuitry sensitive to a subsurface environment and a sensor that detects changes in the circuitry. The sensor detects changes in the circuitry that indicates that the drill bit has struck an underground pipe. The sensor may detect a series of electromagnetic signals indicative of the strike or may detect changes to an impedance bridge at a capacitive sensor.

First claim

What is claimed is:

1 . A crossbore detection system comprising:
a drill bit; a first antenna configured to transmit a series of signals; a second antenna configured to receive the series of signals transmitted by the first antenna; and a sensor to detect changes in the series of signals received by the second antenna indicative of proximity between the drill bit and an underground anomaly.

2 . The crossbore detection system of claim 1 wherein a frequency of the series of signals is between about 1 gigahertz and 8 gigahertz.

3 . The crossbore detection system of claim 1 further comprising a transmitter capable of receiving signals from the sensor and transmitting signals to an above ground receiver.

4 . The crossbore detection system of claim 1 further comprising a housing connected to the drill bit wherein the second antenna is disposed on the housing.

5 . The crossbore detection system of claim 4 wherein the first antenna is disposed on the housing.

6 . The crossbore detection system of claim 1 further comprising an accelerometer.

7 . The crossbore detection system of claim 1 wherein the second antenna comprises a front face, wherein the front face of the second antenna is substantially parallel with the cutting blade.

8 . The crossbore detection system of claim 1 wherein the underground anomaly comprises an underground pipe.

9 . The crossbore detection system of claim 1 herein the underground anomaly comprises a void space.

10 . A system comprising:
a horizontal directional drilling unit; a drill string coupled to the horizontal directional drilling unit; an above ground receiver; the crossbore detection system of claim I located on a distal end of the drill string.

11 . The system of claim 8 wherein the above ground receiver is located at the horizontal directional drilling unit.

12 . A system comprising:
a horizontal directional a drill string rotatable by the horizontal directional drill; a downhole tool coupled to a distal end of the drill string, wherein the downhole tool comprises:
a drill bit; and
a crossbore detection system comprising:
circuitry disposed on the downhole tool and sensitive to changes in the subsurface; and
a sensor capable of detecting variations in the circuitry caused by the drill bit crossing a path of an underground pipe.

13 . The system of claim 12 wherein the circuitry comprises a first electromagnetic transmitting antenna and a second electromagnetic receiving antenna.

14 . The system of claim 13 wherein the first electromagnetic transmitting antenna is disposed on the drill bit.

15 . The system of claim 13 further comprising an accelerometer disposed within the downhole tool.

16 . The system of claim 12 further comprising a transmitter disposed within the downhole tool, wherein the transmitter emits a signal when the sensor detects the variations in the circuitry.

17 . The system of claim 12 wherein the circuitry comprises a plurality of electrodes.

18 . The system of claim 17 wherein the sensor detects an induced voltage between at least two of the plurality of electrodes.

19 . A method for detecting a crossbore in horizontal directional drilling operations comprising:
drilling a borehole with a downhole tool comprising a first antenna, a second antenna, a sensor and a drill bit; transmitting a series of signals from the first antenna to a second antenna; comparing signals received at the second antenna to a reference signal indicative of a crossbore; and generating a warning if the signal received at the second antenna indicates a crossbore.

20 . The method of claim 19 further comprising storing received signal data in the downhole tool and uploading the signal data from at a port.

21 . The method of claim 19 wherein the first antenna is disposed on the drill bit.

22 . The method of claim 19 wherein the series of signals comprise a frequency between about 1 gigahertz to about 5 gigahertz.

23 . The method of claim 19 comprising generating the warning at a drilling machine.

Assignees

• Charles Machine Works
• Louisiana Tech Univ Res Found

Inventors

• Gunsaulis Floyd R
• Sharp Richard F
• Jaganathan Arun Prakash
• Hall David Edward
• Simicevic Neven

Classifications

• E21B47/122 Primary

  Fixed Constructions · mapped topic

• E21B47/02

  Determining slope or direction · CPC title

• E21B7/046

  horizontal drilling (drilling with mechanical conveying means E21B7/003) · CPC title

• E21B47/09 Primary

  Locating or determining the position of objects in boreholes or wells {, e.g. the position of an extending arm}; Identifying the free or blocked portions of pipes · CPC title

• E21B47/013

  Devices specially adapted for supporting measuring instruments on drill bits · CPC title