System for locating a utility with a downhole beacon
AssigneeThe Charles Machine Works, Inc.
InventorScott B. Cole
Life of this patent
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Abstract
A system for locating an underground utility line using a beacon positioned within a downhole tool. The beacon comprises a magnetic sensor formed from one or more ferrite rods. The rods are arranged such that no rod is orthogonal to the longitudinal axis of the beacon housing. The magnetic sensor detects the presence of an underground utility line and sends a signal to an above-ground tracker indicating that a line has been detected. An above-ground locator may be used to determine the position of the line relative the beacon, so that the downhole tool may be steered away from the line.
Claims27
A system, comprising:
- a borehole;
- a drill string situated in the borehole;
- a downhole device carried by the drill string and comprising:
- a housing having a longitudinal axis;
- a magnetic dipole source positioned within the housing;
- a magnetic field sensor formed from two or more ferrite rods arranged such that no rod is orthogonal to the longitudinal axis of the housing;
- and
- an annular member positioned within the housing, in which the two or more ferrite rods are supported by the annular member;
- and
- an above-ground tracker configured to receive data from the downhole device.
A method of using a system, the system comprising:
- a borehole;
- a drill string situated in the borehole;
- a downhole device carried by the drill string and comprising:
- a housing having a longitudinal axis;
- a magnetic dipole source positioned within the housing;
- and
- a magnetic field sensor positioned within the housing and configured to detect a magnetic field along a first axis and a second axis, the first and second axes arranged such that neither axis is orthogonal to the longitudinal axis of the housing;
- and
- an above-ground tracker configured to receive data from the downhole device;
- the method comprising:
- using the magnetic field sensor to make a first set of magnetic field measurements along the first and second axes;
- in which the first axis is orthogonal to the second axis;
- rotating the drill string such that the housing is rotated by an increment;
- after the rotational increment, using the magnetic field sensor to make a second set of magnetic field measurements along the first and second axes;
- and
- using the two sets of field measurements to calculate the magnetic field along a third axis, the third axis orthogonal to the first and second axes.
A method of using a system, the system comprising:
- a borehole;
- a drill string situated in the borehole;
- a downhole device carried by the drill string and comprising:
- a housing having a longitudinal axis;
- a magnetic dipole source positioned within the housing;
- and
- a magnetic field sensor formed from two or more ferrite rods arranged such that no rod is orthogonal to the longitudinal axis of the housing;
- and
- an above-ground tracker configured to receive data from the downhole device;
- the method comprising:
- using the magnetic field sensor to make a first set of magnetic field measurements along a first axis and a second axis, the second axis orthogonal to the first axis, each axis corresponding to one of the ferrite rods;
- rotating the drill string such that the housing is rotated by an increment;
- after the rotational increment, using the magnetic field sensor to make a second set of magnetic field measurements along the first axis and the second axis;
- and
- using the two sets of field measurements to calculate the magnetic field along a third axis, the third axis orthogonal to the first and second axes.
Dependencies are inferred from the claim text.