Casing mounted EM transducers having a soft magnetic layer
First Claim
1. A permanent electromagnetic (EM) monitoring system that comprises:
- a casing string installed inside a borehole, the casing string having at least one EM transducer module that includes;
a wire coil that encircles the casing string; and
a layer of soft magnetic material between the coil and the casing string; and
a well interface system coupled to the at least one EM transducer module to periodically transmit and/or collect EM signals in order to monitor at least one parameter of the subsurface formation over time.
1 Assignment
0 Petitions
Accused Products
Abstract
Illustrative permanent electromagnetic (EM) monitoring systems and methods have a casing string positioned inside a borehole and equipped with one or more EM transducer modules having a layer of soft magnetic material that substantially encircles the casing string to amplify a signal response of a magnetic field transmitting and/or sensing element. The layer preferably has an axial dimension at least twice an axial dimension of the magnetic field sensing element, with a relative permeability at least twice that of the casing material. The magnetic field transmitting element can be a coil. The magnetic field sensing element can be a coil or a piezoelectric or magnetostrictive element that applies stress to an optical fiber. A well interface system communicates with the one or more EM transducer modules to transmit and/or collect EM signals over time. Additional casing strings may be provided in other nearby boreholes to enable tomographic mapping and monitoring of fluid interfaces in the reservoir.
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Citations
27 Claims
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1. A permanent electromagnetic (EM) monitoring system that comprises:
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a casing string installed inside a borehole, the casing string having at least one EM transducer module that includes; a wire coil that encircles the casing string; and a layer of soft magnetic material between the coil and the casing string; and a well interface system coupled to the at least one EM transducer module to periodically transmit and/or collect EM signals in order to monitor at least one parameter of the subsurface formation over time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 24)
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13. A permanent electromagnetic (EM) monitoring method that comprises:
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installing a casing string in a borehole, the casing string including at least one EM transducer module with a layer of soft magnetic material underlying a wire coil that encircles the casing string; establishing communication between a well interface system and the at least one EM transducer module; and employing the at least one EM transducer module to periodically transmit and/or collect EM signals in order to monitor at least one parameter of the subsurface formation over time. - View Dependent Claims (14, 15, 16, 25)
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17. A permanent electromagnetic (EM) monitoring system that comprises:
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a casing string installed inside a borehole, the casing string having at least one EM transducer module that includes; a magnetic field sensing element; and a layer of soft magnetic material that substantially encircles the casing string to amplify a signal response of the magnetic field sensing element; and a well interface system coupled to the at least one EM transducer module to periodically collect EM signals in order to monitor at least one parameter of the subsurface formation over time. - View Dependent Claims (18, 19, 26)
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20. A permanent electromagnetic (EM) monitoring method that comprises:
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installing a casing string in a borehole, the casing string including at least one EM transducer module with a magnetic field sending element and a layer of soft magnetic material that substantially encircles the casing string to amplify a signal response of the magnetic field sensing element; establishing communication between a well interface system and the at least one EM transducer module; and employing the at least one EM transducer module to periodically collect EM signals in order to monitor at least one parameter of the subsurface formation over time. - View Dependent Claims (21, 22, 23, 27)
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Specification