Nuclear magnetic resonance method and apparatus for evaluating a characteristic of a region
AssigneeBaker Hughes Incorporated
InventorsCarl M. Edwards, Daniel T. Georgi
Life of this patent
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Abstract
A method of evaluating a characteristic of a fluid in a region, and a nuclear magnetic resonance (NMR) well logging apparatus for the implementation thereof, is disclosed. A magnetic field gradient is applied to the region, and first and second sequences of magnetic field gradient is applied to the region, with the second sequence differing in a pulse characteristic from the first sequence. A magnetization spectrum resulting from each of the sequences of pulse is captured, and a change in the magnetization spectrum resulting from the first and second sequences of pulses is analyzed to extract information about the fluid.
Claims27
A nuclear magnetic resonance (NMR) well logging apparatus, comprising:
- a field gradient generator operational to apply a static magnetic field gradient to a fluid of a subterranean region;
- a signal generator operational to apply first and second sequences of magnetic pulses to the region;
- a signal receiver operational to receive a NMR signal responsive to the pulses;
- a processing circuit coupled with the signal generator and the signal receiver, the processing circuit being programmed with instructions which, when executed by the processing circuit:
- cause:
- the signal generator to generate first and second sequences of magnetic field pulses to the region;
- the signal receiver to receive a resultant NMR signal from the region;
- and
- cause the processing circuit to:
- capture a magnetization spectrum in response to each of the first and second sequences of magnetic field pulses, the magnetization spectrum being represented as a function of frequency;
- and
- analyze a change in the magnetization spectrum resulting from the first and second sequences and extract therefrom information about the fluid.
A nuclear magnetic resonance (NMR) well logging apparatus, comprising:
- a field gradient generator configured to apply a static magnetic field gradient to a fluid of a subterranean region;
- a signal generator configured to apply first and second sequences of magnetic pulses to the region;
- a signal receiver configured to receive information responsive to the pulses;
- a processing circuit configured to control the pulses and to analyze the received information;
- and
- a storage medium, readable by the processing circuit, storing instructions for execution by the processing circuit for:
- applying first and second sequences of magnetic field pulses to the region;
- capturing a magnetization spectrum resulting from each of the sequences of pulses, the magnetization spectrum being represented as a function of frequency;
- and
- analyzing a change in the magnetization spectrum resulting from the first and second sequences of pulses to extract information about the fluid.
A method of evaluating a characteristic of a fluid in a region, comprising:
- applying a magnetic field gradient to the region;
- applying first and second sequences of magnetic field pulses to the region, the second sequence differing in a pulse characteristic from the first sequence;
- capturing a magnetization spectrum resulting from each of the sequences of pulses, the magnetization spectrum being represented as a function of frequency;
- and
- analyzing a change in the magnetization spectrum resulting from the first and second sequences of pulses to extract information about the fluid.
A method of evaluating a characteristic of a fluid in a region, comprising:
- applying a magnetic field gradient to the region;
- applying first and second sequences of magnetic field pulses to the region, the second sequence differing in a pulse characteristic from the sequence, wherein the applying first and second sequences of magnetic field pulses comprises applying a sequence of equally spaced pulses, and wherein the applying first and second sequences of magnetic field pulses comprises applying a sequence of magnetic field pulses having a power spectrum with an energy distribution across a range of frequencies in a series of closely spaced sticks;
- capturing a magnetization spectrum resulting from each of the sequences of pulses;
- and
- analyzing a change in the magnetization spectrum resulting from the first and second sequences of pulses to extract information about the fluid.
A method of evaluating a characteristic of a fluid in a region, comprising:
- applying a magnetic field gradient to the region;
- applying first and second sequences of magnetic field pulses to the region, each of the sequences having a power spectrum with an energy distribution across a range of frequencies in a series of closely spaced sticks, the second sequence differing in pulse characteristic to the first sequence;
- and
- analyzing a resultant magnetization spectrum to extract information relating to signal attenuation resulting from the characteristics of the fluid in the region, the analyzed magnetization spectrum being represented as a function of frequency.
Dependencies are inferred from the claim text.