Horizontal directional drilling crossbore detector
AssigneeThe Charles Machine Works, Inc.
InventorsFloyd R. Gunsaulis, Richard F. Sharp, Arun Prakash Jaganathan, David Edward Hall, Neven Simicevic
Life of this patent
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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.
Claims25
A crossbore detection system comprising:
- a downhole tool;
- a first antenna and a second antenna supported on the downhole tool and maintained in steady-state communication by electromagnetic signals that propagate along a path interconnecting the two antennas;
- a sensor responsive to the signals emitted from the first antenna and responsive to the signals received at the second antenna;
- and
- a microcontroller configured to analyze the signals emitted from the first antenna compared to the signals received at the second antenna;
- in which the sensor is configured to detect the power of signals emitted from the first antenna and the power of signals received at the second antenna, and in which the microcontroller is configured to analyze the power of signals emitted from the first antenna compared to the power of signals received at the second antenna.
A system comprising:
- a horizontal directional drill;
- 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:
- a first electromagnetic transmitting antenna disposed on the downhole tool configured to transmit a signal;
- a second electromagnetic receiving antenna disposed on the downhole tool and receiving the signal continuously;
- and
- a sensor capable of detecting variations in the signal emitted from the first electromagnetic transmitting antenna as compared to the signal received at the second electromagnetic receiving antenna;
- in which the sensor is capable of detecting variations in the power of the signal emitted from the first electromagnetic transmitting antenna as compared to the power of the signal received at the second electromagnetic receiving antenna;
- and
- a microcontroller for interpreting the detected variations.
A method of operating a downhole tool comprising:
- drilling a borehole with the downhole tool comprising a first antenna, a second antenna, and a sensor;
- transmitting signals from the first antenna to a second antenna through an adjacent subsurface region along a continuous path;
- detecting the signals emitted from the first antenna using the sensor;
- detecting the signals received at the second antenna using the sensor;
- comparing the signals emitted from the first antenna to the signals received at the second antenna;
- in which the sensor detects the power of the signals emitted from the first antenna and detects the power of the signals received at the second antenna, and in which the power of the signals emitted from the first antenna are compared to the power of the signals received at the second antenna.
Dependencies are inferred from the claim text.