Casing collar locator and method for locating casing collars
First Claim
1. A casing collar locator, adapted to detect casing collars disposed in a wellbore, comprising:
- a fiber optic line carrying an optical signal;
a magnetic device adapted to become magnetically connected to a casing collar as the magnetic device passes the casing collar;
a modulator that is functionally connected to the magnetic device;
wherein the optical signal is modulated by the modulator when the magnetic device passes the casing collar;
wherein the optical signal is modulated by imparting a strain on the fiber optic line;
wherein the modulator comprises a fiber-bragg grating incorporated on the fiber optic line.
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Accused Products
Abstract
A system and method to log a wellbore, comprising a logging tool adapted to be deployed in a wellbore environment, the logging tool including at least one sensor for taking a measurement of the wellbore environment. The sensor is a fiber optic sensor and the system includes a fiber optic line in optical communication with the sensor. The data measured by the sensor is transmitted through the fiber optic line on a real time basis to the surface, where the data is processed into a real time display. In one embodiment, the fiber optic sensor is a passive sensor not requiring electrical or battery power. In another embodiment, a continuous tube with one end at the earth'"'"'s surface and the other end in the wellbore is attached to the logging tool and includes the fiber optic line disposed therein.
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Citations
18 Claims
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1. A casing collar locator, adapted to detect casing collars disposed in a wellbore, comprising:
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a fiber optic line carrying an optical signal; a magnetic device adapted to become magnetically connected to a casing collar as the magnetic device passes the casing collar; a modulator that is functionally connected to the magnetic device; wherein the optical signal is modulated by the modulator when the magnetic device passes the casing collar; wherein the optical signal is modulated by imparting a strain on the fiber optic line; wherein the modulator comprises a fiber-bragg grating incorporated on the fiber optic line. - View Dependent Claims (4, 5, 6, 9, 10, 11)
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2. A casing collar locator adapted to detect casing collars disposed in a wellbore, comprising:
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a fiber optic line carrying an optical signal; a magnetic device adapted to become magnetically connected to a casing collar as the magnetic device passes the casing collar; a modulator that is functionally connected to the magnetic device; wherein the optical signal is modulated by the modulator when the magnetic device passes the casing collar; wherein the optical signal is modulated by imparting a strain on the fiber optic line; wherein the magnetic device comprises a permanent magnet and a coil.
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3. A casing collar locator adapted to detect casing collars disposed in a wellbore, comprising:
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a fiber optic line carrying an optical signal; a magnetic device adapted to become magnetically connected to a casing collar as the magnetic device passes the casing collar; a modulator that is functionally connected to the magnetic device; wherein the optical signal is modulated by the modulator when the magnetic device passes the casing collar; wherein the optical signal is modulated by imparting a strain on the fiber optic line; wherein the magnetic connection generates a voltage that causes a piezoelectric material mechanically coupled to the fiber optic line to constrict and strain the fiber optic line.
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7. A casing collar locator adapted to detect casing collars disposed in a wellbore, comprising:
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a fiber optic line carrying an optical signal; a magnetic device adapted to become magnetically connected to a casing collar as the magnetic device passes the casing collar; a modulator that is functionally connected to the magnetic device; wherein the optical signal is modulated by the modulator when the magnetic device passes the casing collar; wherein the modulator moves in relation to the fiber optic line to cause the modulation of the optical signal; wherein the magnetic device comprises a permanent magnet and a moving magnet and the moving magnet moves in relation to the permanent magnet when the magnetic device passes the casing collar; wherein movement of the moving magnet causes the movement of the modulator in relation to the fiber optic line; wherein the moving magnet is biased to a stationary position by a spring. - View Dependent Claims (12)
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8. A casing collar locator adapted to detect casing collars disposed in a wellbore, comprising:
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a fiber optic line carrying an optical signal; a magnetic device adapted to become magnetically connected to a casing collar as the magnetic device passes the casing collar; a modulator that is functionally connected to the magnetic device; wherein the optical signal is modulated by the modulator when the magnetic device passes the casing collar; wherein the modulator moves in relation to the fiber optic line to cause the modulation of the optical signal; wherein the magnetic device comprises a permanent magnet and a moving magnet and the moving magnet moves in relation to the permanent magnet when the magnetic device passes the casing collar; wherein movement of the moving magnet causes the movement of the modulator in relation to the fiber optic line; wherein the modulator comprises a component having alternately placed black and white lines.
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13. A method for identifying the location of casing collars disposed in a wellbore, comprising:
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providing a magnetic device adapted to become magnetically connected to a casing collar as the magnetic device passes the casing collar; and modulating an optical signal transmitted through a fiber optic line when the magnetic device passes the casing collar; wherein the modulating step comprises imparting a strain on the fiber optic line; wherein the imparting step comprises creating a magnetic connection between the magnetic device and the casing collar when the magnetic device passes the casing collar; and
generating a voltage that causes a piezoelectric material mechanically coupled to the fiber optic line to constrict and strain the fiber optic line. - View Dependent Claims (14, 15, 17)
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16. A method for identifying the location of casing collars disposed in a wellbore, comprising:
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providing a magnetic device adapted to become magnetically connected to a casing collar as the magnetic device passes the casing collar; and modulating an optical signal transmitted through a fiber optic line when the magnetic device passes the casing collar; wherein the modulating step comprises moving a modulator in relation to the fiber optic line; wherein the moving step comprises moving a moving magnet in relation to a permanent magnet when the magnetic device passes the casing collar; the method further comprising biasing the moving magnet to stationary position by use of spring. - View Dependent Claims (18)
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Specification