NMR flow metering using velocity selection and remote detection
First Claim
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1. A method of estimating a flow rate of a phase of a fluid having a plurality of components, the method comprising:
- using a magnet for polarizing nuclei of the fluid flowing over a plurality of distances wherein a number of the distances is equal to or greater than a number of the components;
measuring a magnetization of the polarized nuclei for each of the plurality of distances for a selected flow velocity;
using the plurality of measured magnetizations for estimating a relative fraction of each of the plurality of components corresponding to the selected velocity;
wherein measuring the magnetization of the polarized nuclei further comprises pulsing a first coil with a tipping pulse, pulsing a second coil with a refocusing pulse, and measuring an echo resulting from the refocusing pulse with a third coil.
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Abstract
A method and apparatus for estimating a flow rate of a phase of a multiphase fluid is disclosed. In the first method, nuclei in the fluid are polarized over two distances and a measured magnetization gives the relative fraction of two components of the fluid for a selected velocity. In the second method, nuclei in the fluid are polarized over a specified distance and measurements of the decay of spin echo signals is used to give the relative fraction of two components of the fluid for the selected velocity.
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Citations
26 Claims
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1. A method of estimating a flow rate of a phase of a fluid having a plurality of components, the method comprising:
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using a magnet for polarizing nuclei of the fluid flowing over a plurality of distances wherein a number of the distances is equal to or greater than a number of the components; measuring a magnetization of the polarized nuclei for each of the plurality of distances for a selected flow velocity; using the plurality of measured magnetizations for estimating a relative fraction of each of the plurality of components corresponding to the selected velocity; wherein measuring the magnetization of the polarized nuclei further comprises pulsing a first coil with a tipping pulse, pulsing a second coil with a refocusing pulse, and measuring an echo resulting from the refocusing pulse with a third coil. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus configured to estimate a flow rate of a phase of a fluid having a plurality of components, the apparatus comprising:
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a magnet configured to polarize nuclei of the fluid flowing over a plurality of distances wherein a number of the distances is equal to or greater than a number of the components; a coil arrangement configured to measure a magnetization of the polarized nuclei for each of the plurality of distances for a selected flow velocity, wherein the coil arrangement further comprises a first coil configured to pulse the polarized nuclei with a tipping pulse, a second coil configured to pulse the polarizing nuclei with a refocusing pulse, and a third coil configured to measure an amplitude of an echo resulting from the refocusing pulse; a processor configured to use the plurality of measured magnetizations to estimate a relative fraction of each of the plurality of components corresponding to the selected velocity. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method of estimating a flow rate of a phase of a fluid having a plurality of components, the method comprising:
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using a magnet for polarizing nuclei of the fluid flowing over a selected distance; pulsing the polarized nuclei with a tipping pulse with a first coil, a refocusing pulse with a second coil at a first distance from the first coil, a refocusing pulse with a third coil at a second distance from the first coil, and measuring an echo signal for each of the plurality of distances for a selected flow velocity; using the plurality of echo signals for estimating a relative fraction of each of the plurality of components corresponding to the selected velocity. - View Dependent Claims (15, 16, 17, 18, 19)
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20. An apparatus configured to estimate a flow rate of a phase of a fluid having a plurality of components, the apparatus comprising:
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a magnet configured to polarize nuclei of the fluid flowing over a selected distance; a first coil arrangement configured to pulse the polarized nuclei with a tipping pulse, a second coil at a first distance from the first coil configured to pulse the polarized nuclei with a refocusing pulse, the third coil at a second distance from the first coil configured to pulse the polarized nuclei with a refocusing pulse, and at least one additional coil configured to measure and echo signal for each of the plurality of distances for a selected flow velocity; and a processor configured to use the plurality of echo signals to estimate a relative fraction of each of the plurality of components corresponding to the selected velocity. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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Specification