Method and apparatus for well-bore proximity measurement while drilling
First Claim
1. A method of determining a distance between a first borehole and a second borehole, the method comprising:
- (a) inducing a magnetization in a magnetic object in the first borehole;
(b) producing a first signal and a second signal each responsive to a magnetic flux resulting from the magnetization in the magnetic object respectively using a first coil and a second coil in the second borehole; and
(c) combining the first signal and the second signal to reduce effect of earth'"'"'s magnetic field from the combined signal; and
(d) estimating the distance between the first borehole from the second borehole using the combined signal.
1 Assignment
0 Petitions
Accused Products
Abstract
An apparatus for determining a distance between a first borehole and a second borehole is provided that in one embodiment includes a rotating magnet on a tool configured for placement in the second borehole for inducing magnetization in a magnetic object in the first borehole, a first coil and a second coil placed radially symmetrically with respect to an axis of the tool, the first coil providing a first signal and second coil providing a second signal responsive to a magnetic flux resulting from the magnetization in the magnetic object in the first borehole, and a controller configured to combine the first signal and the second signal and determining distance between the first borehole and the second borehole using the combined signal.
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Citations
21 Claims
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1. A method of determining a distance between a first borehole and a second borehole, the method comprising:
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(a) inducing a magnetization in a magnetic object in the first borehole; (b) producing a first signal and a second signal each responsive to a magnetic flux resulting from the magnetization in the magnetic object respectively using a first coil and a second coil in the second borehole; and (c) combining the first signal and the second signal to reduce effect of earth'"'"'s magnetic field from the combined signal; and (d) estimating the distance between the first borehole from the second borehole using the combined signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of determining a distance between a first borehole and a second borehole, the method comprising:
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(a) inducing a magnetization in a magnetic object in the first borehole; (b) producing a first signal, a second signal and a third signal, each such signal responsive to a magnetic flux resulting from the magnetization in the magnetic object respectively using a first coil, second coil and third coil in the second borehole; and (c) combining the first signal and the second signal to produce a fourth signal that is substantially free of an effect of the earth'"'"'s magnetic field and combining the first signal and the third signal to produce a fifth signal that is substantially free of the effect of the earth'"'"'s magnetic field, (d) estimating the distance between the first borehole and the second borehole using the fourth signal and the fifth signal. - View Dependent Claims (8, 9, 10, 11)
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12. An apparatus for determining a distance between a first borehole and a second borehole, comprising:
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a rotating magnet on a tool configured to be placed in the second borehole for inducing magnetization in a magnetic object in the first borehole; a first coil and a second coil placed radially symmetrically with respect to an axis associated with the second borehole, the first coil providing a first signal and second coil providing a second signal responsive to a magnetic flux resulting from the magnetization in the magnetic object in the first borehole; and a controller configured to combine the first signal and the second signal and determining the distance between the first borehole and the second borehole using the combined signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A drilling assembly:
- comprising;
a magnet configured to induce magnetization in an spaced apart magnetic object; at least two coils wherein at least one of the two coils includes a pair of substantially identical coils placed symmetrically on a member in the drilling assembly; a controller configured to determine a distance between the object and the drilling assembly during a drilling operation from a difference of voltages provided by the pair of the coils responsive to the magnetization of the object. - View Dependent Claims (21)
- comprising;
Specification