1. A method for identifying the location of a binding zone between a stuck tubular and a borehole, the method comprising the steps of:
providing a magnetizing module having a longitudinal axis, wherein the step of providing a magnetizing module further comprises the step of orienting two permanent, longitudinal magnets along the longitudinal axis of the magnetizing module in an opposing magnetic orientation to produce a magnetic B field that extends in a substantially radial direction;
magnetizing the tubular with the magnetizing module;
applying a stress to the tubular;
passing a magnetic field sensor through the tubular on a scanning pass;
measuring a stress-induced demagnetization of the tubular with the magnetic field sensor; and
analyzing the stress-induced demagnetization of the tubular to identify locations within the tubular that are exposed to increased stress.
2. The method of claim 1, wherein the step of magnetizing the tubular further comprises:
passing the magnet through the tubular on a baseline magnetization pass to magnetize the tubular; and
measuring the baseline magnetization of the tubular with the magnetic field sensor.
3. The method of claim 2, wherein the analyzing step further comprises comparing the baseline magnetization of the tubular against the stress-induced magnetization of the tubular comprises graphically plotting the baseline magnetization against the stress-induced magnetization.
4. The method of claim 2, wherein the step of measuring a baseline magnetization of the tubular is conducted during the baseline magnetization pass.
5. The method of claim 2, wherein the step of passing the magnet through the tubular on a baseline magnetization pass further comprises the step of magnetizing the tubular in a substantially radial direction.
6. The method of claim 1, wherein the step of applying a stress to the tubular comprises lifting the stuck tubular to create an axial stress.
7. The method of claim 1, wherein the step of applying a stress to the tubular comprises applying a torque to the tubular to create a torsional stress.
8. The method of claim 1, wherein the step of applying a stress to the tubular comprises applying an axial stress and a torsional stress.
9. A method for magnetizing a stuck tubular within a wellbore, the method comprising the steps of:
providing a magnetizing module having a longitudinal axis, wherein the step of providing a magnetizing module further comprises the step of orienting two permanent, longitudinal magnets along the longitudinal axis of the magnetizing module in an opposing magnetic orientation to produce a magnetic B field that extends in a substantially radial direction; and
passing the magnetizing module through the tubular on a baseline magnetization pass to magnetize the tubular in a predominately radial direction.
10. A device for detecting the location of a binding zone between a stuck tubular and a borehole, the device comprising:
a first magnet having an interior magnetic pole and an exterior magnetic pole;
a second magnet having an interior magnetic pole and an exterior magnetic pole, wherein the interior magnetic poles of the first and second magnets are of like polarity and positioned proximate to one another within the device; and
a sensor.
11. The device of claim 10, wherein the first and second magnets are longitudinal magnets, and wherein the first and second longitudinal magnets are oriented in a magnetically opposed manner to create a magnetic B field extending in a radial direction.
12. The device of claim 10, further comprising a lower module, an upper module and a center module between the upper and lower modules.
13. The device of claim 12, wherein the first and second magnets are located within the lower module.
14. The device of claim 13, wherein the sensor is located within the upper module.
15. The device of claim 12, wherein each of the upper, lower and center modules includes a housing manufactured from a non-magnetic material.
16. The device of claim 10, wherein the sensor is selected from the group consisting of search coils, Hall Effect sensors and giant magnetoresistance (GMR) sensors.
17. The device of claim 16, further comprising a plurality of sensors.
18. The device of claim 10, further comprising an umbilical extending from the sensor.
19. The device of claim 10, wherein the tubular is a well casing.
20. The device of claim 10, wherein the tubular is a drill string.
21. The device of claim 10, further comprising a monitor for displaying the measurements made by the sensor.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A filter circuit comprising:
a first band-pass filter, a second band-pass filter, a third band-pass filter and a fourth band-pass filter each having an input terminal and an output terminal;
a first terminal to which the output terminal of the first band-pass filter and the output terminal of the second band-pass filter are connected in common;
a second terminal to which the output terminal of the third band-pass filter and the output terminal of the fourth band-pass filter are connected in common;
a third terminal to which the input terminal of the first band-pass filter and the input terminal of the fourth band-pass filter are connected in common; and
a fourth terminal to which the input terminal of the second band-pass filter and the input terminal of the third band-pass filter are connected in common,
wherein whole pass bands of the first band-pass filter, the second band-pass filter, the third band-pass filter and the fourth band-pass filter differ from each other.
2. The filter circuit according to claim 1, wherein
the pass bands of the first band-pass filter and the second band-pass filter are lower than the pass bands of the third band-pass filter and the fourth band-pass filter.
3. The filter circuit according to claim 2, wherein
the first terminal is a terminal to be connected to a first amplifier, the second terminal is a terminal to be connected to a second amplifier, and the third terminal and the fourth terminal are terminals to which a switch is connected, the switch selecting one of the third terminal and the fourth terminal and connecting the selected one of the third terminal and the fourth terminal to an antenna.
4. A module comprising:
a filter circuit according to claim 2; and
a switch that selects any one of the third terminal and the fourth terminal and connect the selected one of the third terminal and the fourth terminal to an antenna.
5. A module comprising:
a filter circuit according to claim 2;
a first amplifier connected to the first terminal; and
a second amplifier connected to the second terminal.
6. A module comprising:
a filter circuit according to claim 2;
a switch that selects any one of the third terminal and the fourth terminal and connect the selected one of the third terminal and the fourth terminal to an antenna;
a first amplifier connected to the first terminal; and
a second amplifier connected to the second terminal.
7. The filter circuit according to claim 1, wherein
at least one of the first terminal and the second terminal includes a pair of balanced terminals.
8. A module comprising:
a filter circuit according to claim 1.
9. The filter circuit according to claim 1, wherein
at least one of the first terminal and the second terminal includes an unbalanced terminal.
10. The filter circuit according to claim 9, wherein
each of the third terminal and the fourth terminal includes an unbalanced terminal.
11. A filter circuit comprising:
a first band-pass filter, a second band-pass filter, a third band-pass filter and a fourth band-pass filter each having an input terminal and an output terminal;
a first terminal to which the input terminal of the first band-pass filter and the input terminal of the second band-pass filter are connected in common;
a second terminal to which the input terminal of the third band-pass filter and the input terminal of the fourth band-pass filter are connected in common;
a third terminal to which the output terminal of the first band-pass filter and output terminal of the fourth band-pass filter are connected in common; and
a fourth terminal to which the output terminal of the second band-pass filter and the output terminal of the third band-pass filter are connected in common,
wherein whole pass bands of the first band-pass filter, the second band-pass filter, the third band-pass filter and the fourth band-pass filter differ from each other.
12. The filter circuit according to claim 11, wherein
the pass bands of the first band-pass filter and the second band-pass filter are lower than the pass bands of the third band-pass filter and the fourth band-pass filter.
13. The filter circuit according to claim 12, wherein
the first terminal is a terminal to be connected to a first amplifier, the second terminal is a terminal to be connected to a second amplifier, and the third terminal and the fourth terminal are terminals to which a switch is connected, the switch selecting one of the third terminal and the fourth terminal and connecting the selected one of the third terminal and the fourth terminal to an antenna.
14. A module comprising:
a filter circuit according to claim 11.