Nuclear magnetic reasonance fluid characterization apparatus and method for using with electric wireline formation testing instruments
First Claim
1. A method for characterizing a fluid sample withdrawn from an earth formation, comprising:
- performing magnetic resonant spin echo measurements on said fluid sample at a magnetic resonant frequency of carbon-13;
summing amplitudes of said spin echo measurements;
spectrally analyzing said summed amplitudes;
determining whether aromatic hydrocarbons are present in said fluid sample by measuring an amplitude of said spectrally analyzed summed amplitudes at about 130 parts per million shift from said carbon-13 resonant frequency and determining whether aliphatic hydrocarbons are present in said fluid sample by measuring an amplitude of said spectrally analyzed summed amplitudes at about 30 parts per million frequency shift from said carbon-13 resonant frequency.
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Abstract
A method for characterizing a fluid sample withdrawn from an earth formation. The method includes performing nuclear magnetic resonant spin echo measurements on the fluid sample at a nuclear magnetic resonant frequency of carbon-13. Amplitudes of the spin echo measurements are summed. The summed measurements are spectrally analyzed. The fluid is characterized by determining whether aromatic hydrocarbons are present by measuring an amplitude of the spectrally analyzed spin echo measurements at about 130 part per million shift from the carbon-13 frequency. The fluid is also characterized by determining whether aliphatic hydrocarbons are present by measuring an amplitude of the spectrally analyzed spin echo measurements at about 30 parts per million frequency shift.
75 Citations
17 Claims
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1. A method for characterizing a fluid sample withdrawn from an earth formation, comprising:
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performing magnetic resonant spin echo measurements on said fluid sample at a magnetic resonant frequency of carbon-13; summing amplitudes of said spin echo measurements; spectrally analyzing said summed amplitudes; determining whether aromatic hydrocarbons are present in said fluid sample by measuring an amplitude of said spectrally analyzed summed amplitudes at about 130 parts per million shift from said carbon-13 resonant frequency and determining whether aliphatic hydrocarbons are present in said fluid sample by measuring an amplitude of said spectrally analyzed summed amplitudes at about 30 parts per million frequency shift from said carbon-13 resonant frequency. - View Dependent Claims (2, 3, 4)
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5. An apparatus for characterizing a fluid sample withdrawn from an earth formation, comprising:
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a magnet for inducing a substantially homogeneous static magnetic field in at least a portion of said sample; a first antenna for inducing a radio frequency magnetic field in said at least a portion of said sample, said radio frequency magnetic field substantially perpendicular to a magnetization direction of said static magnetic field; circuits coupled to said antenna for performing nuclear magnetic resonance spin echo measurements at a nuclear magnetic resonant frequency of carbon-13, said circuits including means for stacking said spin echo measurements over a measurement sequence; and a spectral analyzer for measuring amplitudes of components of said spin echo measurements at frequency shifts of 30 and 130 parts per million from said resonant frequency. - View Dependent Claims (6, 7, 8)
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9. An apparatus for characterizing a fluid sample withdrawn from an earth formation, comprising:
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a probe for selective hydraulic engagement with said earth formation; a pump coupled to said probe for selectively withdrawing said fluid sample from said formation; and a nuclear magnetic resonance sensor in hydraulic communication with said pump and said probe, said sensor comprising a magnet for inducing a substantially homogeneous static magnetic field in at least a portion of said sample, a first antenna for inducing a radio frequency magnetic field in said at least a portion of said sample, said radio frequency magnetic field substantially perpendicular to a magnetization direction of said static magnetic field, circuits coupled to said antenna for performing nuclear magnetic resonance spin echo measurements at a nuclear magnetic resonant frequency of carbon-13, said circuits including means for stacking said spin echo measurements over a measurement sequence, and a spectral analyzer for measuring amplitudes of components of said spin echo measurements at frequency shifts of 30 and 130 parts per million from said resonant frequency. - View Dependent Claims (10, 11, 12)
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13. A method for characterizing a fluid sample withdrawn from an earth formation, comprising:
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placing a probe in hydraulic communication with said earth formation, said probe forming part of an electric wireline formation testing instrument; withdrawing fluid by operating a pump in selective hydraulic communication with said probe; conducting said fluid into a sample chamber disposed in said instrument for performing nuclear magnetic resonance measurements on said fluid therein, said measurements comprising performing magnetic resonant spin echo measurements on said fluid sample at a nuclear magnetic resonant frequency of carbon-13, summing amplitudes of said spin echo measurements, spectrally analyzing said summed amplitudes, and determining whether aromatic hydrocarbons are present in said fluid sample by measuring an amplitude of said spectrally analyzed summed amplitudes at about 130 part per million shift from said carbon-13 frequency and determining whether aliphatic hydrocarbons are present in said fluid sample by measuring an amplitude of said spectrally analyzed summed amplitudes at about 30 parts per million frequency shift. - View Dependent Claims (14, 15, 16, 17)
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Specification