Electricity: measuring and testing – Particle precession resonance – Using well logging device
Patent
1997-12-30
2000-10-17
Oda, Christine K.
Electricity: measuring and testing
Particle precession resonance
Using well logging device
324309, G01V 300
Patent
active
06133734&
ABSTRACT:
This invention makes an NMR measurement at extended depths into the formation using the earth's magnet field to generate an NMR measurement and using a magnet field from a permanent magnetic to suppress the NMR signal in the borehole and shallow formation. The magnetic field from a permanent magnet increases the Larmor frequency in the borehole and the shallow earth formation. An oscillator applies an RF magnetic field to the formation for a period of time in order to align nuclei spins approximately perpendicular to the earth's magnetic field. At the end of this period, the field is turned off rapidly. Since the spins are unable to follow this sudden change, they are left aligned perpendicular to the earth's field. These nuclei precess about the earth's field at the approximate Larmor frequency of the earth's field. The RF receiver detects the RF signals in the approximate frequency range of the Larmor frequency. Borehole and shallow formation protons precessing at the high frequencies resulting from the permanent magnet are not detected by the receiver. Therefore, the receiver only detects signals from greater depths in the earth's formation.
REFERENCES:
patent: 4528508 (1985-07-01), Vail, III
patent: 4656422 (1987-04-01), Vail, III et al.
patent: 4710713 (1987-12-01), Strikman
patent: 4724385 (1988-02-01), Vail, III
patent: 4804918 (1989-02-01), Vail, III
patent: 5363041 (1994-11-01), Sezginer
patent: 5428291 (1995-06-01), Thomann et al.
patent: 5596274 (1997-01-01), Sezginer
DV Trushkin, OA.Shushakov & AV Legchenko, "Surface NMR Applied to an Electroconductive Medium," Geophysical Prospecting 43, pp. 623-633 (1995).
OA Shushakov, "Surface NMR Measurement of Proton Relaxation Times in Medium to Coarse-Grained Sand Aquifer," Magnetic Resonance Imaging, v. 14, Nos. 7/8, pp. 959-960 (1996).
SC Bushong, "Gradient Echo Imaging," Magnetic Resonance Imaging, Physical and Biological Principles, 2.sup.nd Ed., Mosby Press, NY, pp. 279-297 (1995).
BF Melton & VL Pollack, "Optimizing Sudden Passage in the Earth's-Field NMR Technique," J. Magnetic Resonance, Series A 122, pp. 42-49 (1996).
I Solomon, "Rotary Spin Echoes," Physical Rev. Letters, v. 2, No. 7, pp. 301-302 (Apr. 1, 1959).
EJ Wells & KH Abramson, "High Resolution NMR Rotary Echoes," J. Magnetic Resonance 1, pp. 378-392 (1969).
T Hwang, PCM van Zijl & M Garwood, "Fast Broadband Inversion by Adiabatic Pulses," J. Magnetic Resonance 133, pp. 200-203 (1998).
M Garwood & K Ugurbil, "B.sub.1 Insensitive Adiabatic RF Pulses," NMR Basic Principles and Progess, v. 26, Springer-Verlag, NY NY, pp. 109-147 (1992).
A Tannus & M Garwood, "Improved Performance of Frequency-swept Pulses using Offset-Independent Adiabaticity," J. Magnetic Resonance, Series A 120, pp. 133-137 (1996).
E Kupce & R Freeman, "Optimized Adiabatic Pulses for Wideband Spin Inversion," J. Magnetic Resonance, Series A 118, pp. 299-303 (1996).
T Hwang & AJ Shaka, "Water Suppression that Works, Excitation Sculpting using Arbitrary Waveforms and Pulsed Field Gradients," J. Magnetic Resonance, Series A 112, pp. 275-279 (1995).
MH Levitt & R Freeman, "Compensation for Pulse Imperfections in NMR Spin-Echo Experiments," J. Magnetic Resonance 43, pp. 65-80 (1981).
VL Ermakov, J-M Bohlen & G Bodenhausen, "Improved Schemes for Refocusing with Frequency-Modulated Chirp Pulses," J. Magnetic Resonance, Series A 103, pp. 226-229 (1993).
S Conolly, D Nishimura & A Macovski, "A Selective Adiabatic Spin-Echo Pulse," J. Magnetic Resonance 83, pp. 324-334 (1989).
M Garwood & Y ke, "Symmetric Pulses to Induce Arbitrary Flip Angles with Compensation for RF Inhomogeneity and Resonance Offsets," J. Magnetic Resonance 94, pp. 511-525 (1991).
T-L Hwang, PCM van Zul & M Garwood, "Broadband Adiabatic Refocusing without Phase Distortion," J. Magnetic Resonance 124, pp. 250-254 (1997).
RA de Graaf, K Nicolay & M Garwood, "Single-Shot B.sub.1 -Insensitive Slice Selection with a Gradient-Modulated Adiabatic Pulse, BISS-8," Center for Magnetic Resonance Research and Dep't of Radiology, Univ. of Minn. Medical School, Minneapolis, Minnesota, pp. 652-654 (1996).
A Abragam, "Macroscopic Aspects of Nuclear Magnetism," The Principles of Nuclear Magnetism, Ch. III, pp. 65-68; 86; Fig's III5 and III6, Clarendon Press, Oxford (1961).
DMS Bagguley, ed., "Imaging by Nuclear Magnetic Resonance," Pulsed Magnetic Resonance: NMR, ESR, and Optics, Ch. 14, pp. 317-345, Clarendon Press, Oxford (1992). (Based on a review by P. Mansfield in J. Phys. E., 21, 18 (1988)).
S Conolly, G Glover, D Nishimura & A Macovski, "A Reduced Power Selective Adiabatic Spin-Echo Pulse Sequence," Magnetic Resonance in Medicine 18, pp. 28-38 (1991).
RA Webb, "New Technique for Improved Low-Temperature Squid NMR Measurements," Rev. Sci. Instrum., v. 48, No. 12, pp. 1585-1594 (Dec. 1977).
RR Ernst, G Bodenhausen & A Wokaun, "One-Dimensional Fourier Spectroscopy," Principles of Nuclear Magnetic Resonance in One and Two Dimensions, Chapter 4, pp. 90-239, Clarendon Press, Oxford (1987).
R.C. Herrick, S.H. Couturie & D.L. Best, "An Improved Nuclear Magnetism Logging System and Its Application to Formation Evaluation", Sep. 23-26, 1979, Las Vegas, Nevada, SPE8361.
Jeffery Brigitte L.
Oda Christine K.
Ryberg John J.
Schlumberger Technology Corporation
Shrivastav Brij B.
LandOfFree
Method and apparatus for evaluating an earth formation using nuc does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for evaluating an earth formation using nuc, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for evaluating an earth formation using nuc will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-472695