Nuclear magnetic resonance well logging apparatus and method adapted for measurement-while-drilling
First Claim
1. A nuclear magnetic resonance sensing apparatus, comprising:
- a magnet for inducing a static magnetic field in materials to be analyzed, said static magnetic field substantially rotationally symmetric about a longitudinal axis of said magnet, said static magnetic field substantially perpendicular to said longitudinal axis, said static magnetic field having substantially equal amplitude along said longitudinal axis;
means for generating a radio frequency magnetic field in said materials to be analyzed, said radio frequency magnetic field substantially rotationally symmetric about said longitudinal axis, said radio frequency magnetic field substantially parallel to said longitudinal axis within a sensitive volume containing said materials to be analyzed; and
means for receiving a nuclear magnetic resonance signal from said sensitive volume.
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Accused Products
Abstract
A nuclear magnetic resonance sensing apparatus including a magnet for inducing a static magnetic field in materials to be analyzed, the magnetic field having uniform field strength around, being substantially rotationally symmetric and perpendicular to a longitudinal axis of the magnet. The apparatus includes means for generating a radio frequency magnetic field in the materials to be analyzed. The radio frequency magnetic field is substantially rotationally symmetric about the longitudinal axis and is parallel to the longitudinal axis within a sensitive volume containing the materials to be analyzed. The apparatus includes means for receiving a nuclear magnetic resonance signal from the sensitive volume. In a preferred embodiment, the means for generating and means for receiving include an antenna coil wound so that turns of the coil lie in planes perpendicular to the longitudinal axis of the magnet.
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Citations
23 Claims
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1. A nuclear magnetic resonance sensing apparatus, comprising:
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a magnet for inducing a static magnetic field in materials to be analyzed, said static magnetic field substantially rotationally symmetric about a longitudinal axis of said magnet, said static magnetic field substantially perpendicular to said longitudinal axis, said static magnetic field having substantially equal amplitude along said longitudinal axis; means for generating a radio frequency magnetic field in said materials to be analyzed, said radio frequency magnetic field substantially rotationally symmetric about said longitudinal axis, said radio frequency magnetic field substantially parallel to said longitudinal axis within a sensitive volume containing said materials to be analyzed; and means for receiving a nuclear magnetic resonance signal from said sensitive volume. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A nuclear magnetic resonance well logging apparatus adapted for measurement-while-drilling, comprising:
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a drill collar adapted to be connected within a drilling assembly; a magnet disposed on said drill collar for inducing a static magnetic field in materials to be analyzed, said static magnetic field substantially rotationally symmetric about a longitudinal axis of said magnet, said static magnetic field substantially perpendicular to said longitudinal axis, said static magnetic field having substantially equal amplitude along said longitudinal axis; means for generating a radio frequency magnetic field in said materials to be analyzed, said means for generating disposed on said drill collar, said radio frequency magnetic field substantially rotationally symmetric about said longitudinal axis and parallel to said longitudinal axis within a sensitive volume containing said materials to be analyzed; and means for receiving a nuclear magnetic resonance signal from said sensitive volume. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method for nuclear magnetic resonance measurement, comprising:
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inducing a static magnetic field in materials to be analyzed, said static magnetic field having substantially uniform field strength along a longitudinal axis, said static magnetic field substantially rotationally symmetric about said longitudinal axis and substantially perpendicular to said longitudinal axis; generating a radio frequency magnetic field in said materials to be analyzed, said radio frequency magnetic field substantially rotationally symmetric about said longitudinal axis and substantially parallel to said longitudinal axis within a sensitive volume containing said materials to be analyzed; and receiving a nuclear magnetic resonance signal from said sensitive volume. - View Dependent Claims (17, 18, 19)
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20. A method of logging a wellbore to determine nuclear magnetic resonance properties of earth formation surrounding said wellbore, comprising:
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inducing a static magnetic field in said earth formations, said static magnetic field having substantially uniform field strength along a longitudinal axis, said static magnetic field substantially rotationally symmetric about said longitudinal axis and substantially perpendicular to said longitudinal axis; generating a radio frequency magnetic field in said earth formations, said radio frequency magnetic field substantially rotationally symmetric about said longitudinal axis and parallel to said longitudinal axis within a sensitive volume positioned within said earth formations; receiving a nuclear magnetic resonance signal from said sensitive volume. - View Dependent Claims (21, 22, 23)
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Specification