Method and apparatus for NMR measurement of magnetic materials
AssigneeSchlumberger Technology Corporation
InventorsMartin D. Hurlimann, Abigail Matteson, Jermane Edward Massey, David F. Allen
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Abstract
The present invention relates to a method and apparatus for determining the presence of magnetic materials in a media, such as an earth formation. More specifically, the method of the present invention correlates a diffusion-relaxation calibration function representative of magnetic materials with a 2-D function developed using diffusion-editing to determine the presence and relative content of magnetic materials in a media.
Claims29
A method of extracting information about a fluid-containing porous media comprising:
- a) applying a magnetic field gradient to said media;
- b) applying a first series of oscillating magnetic field pulses to said media, said first series of pulses having an initial magnetic field pulse, a first portion followed by a second portion;
- c) detecting magnetic resonance signals generated in (b);
- d) after a wait time, applying a second series of oscillating magnetic field pulses to said media, said second series of pulses having an initial magnetic field pulse, a third portion followed by said second portion;
- e) detecting magnetic resonance signals generated in (d);
- and
- f) analyzing said detected signals to determine the presence of one or more magnetic materials in said media.
A method of extracting information about a region of fluid-containing earth formation comprising:
- a) applying a magnetic field gradient to said region of earth formation;
- b) applying a first series of oscillating magnetic field pulses to said region of earth formation, said first series of pulses having an initial magnetic field pulse, a first portion followed by a second portion;
- c) detecting magnetic resonance signals generated in (b);
- d) after a wait time, applying a second series of oscillating magnetic field pulses to said region of earth formation, said second series of pulses having an initial magnetic field pulse, a third portion followed by said second portion;
- e) detecting magnetic resonance signals generated in (d);
- and
- f) analyzing said detected signals to determine the presence of one or more magnetic minerals in said region of earth formation.
A logging apparatus comprising:
- a logging tool that is moveable through a borehole;
- and
- a processor that is coupled with the logging tool, the processor being programmed with instructions which, when executed by the processor:
- cause the logging tool to:
- i) generate a first series of oscillating magnetic field pulses to said region of earth formation, the first series having an initial magnetic field pulse, a first portion followed by a second portion;
- ii) detect magnetic resonance signals produced from the region of earth formation;
- iii) after a wait time, apply a second series of oscillating magnetic field pulses to said region of earth formation, said second series having an initial magnetic field pulse, a third portion followed by said second portion;
- iv) detect magnetic resonance signals produced from the region of earth formation;
- and
- cause the processor to:
- v) analyze the detected magnetic resonance signals to determine the presence of magnetic minerals in the region of investigation.
Dependencies are inferred from the claim text.