Electricity: measuring and testing – Particle precession resonance – Using well logging device
Patent
1991-02-19
1992-10-06
Tokar, Michael J.
Electricity: measuring and testing
Particle precession resonance
Using well logging device
G01R 3320
Patent
active
051535149
ABSTRACT:
An apparatus is disclosed for investigating nuclear magnetic resonance properties of earth formations traversed by a borehole, including a logging device adapted for longitudinal movement in the borehole. The device includes a first subsystem for producing a static magnetic field in the formations and a second subsystem for transmitting electromagnetic energy into the formations and for detecting electromagnetic energy from the formations. The second subsystem comprises an antenna assembly which includes an open-ended shell formed of a magnetically permeable material. An open-ended electrically conductive body is disposed within the shell and is spaced therefrom. A medium whose acoustic impedance is substantially different than the acoustic impedance of the shell and the body is disposed between the shell and the body. An electrically conductive probe is disposed in the body, and an electrically insulating magnetically permeable loading material disposed in the body. The shell is formed of a material having a magnetic permeability that is high enough to render the magnetic reluctance of the loading material several times the magnetic reluctance of the shell. The body is formed of a metal having thickness that is at least several skin depths in said metal at the frequency of the electromagnetic energy and is less than the minimum thickness that would support an acoustic resonance mode in its thickness direction at the frequency of the electromagnetic energy. The apparatus provides a shunt path for the static magnetic field in the region of the antenna that would otherwise have a deleterious effect on the loading material of the antenna and on antenna operation. The apparatus also minimizes undesirable ringing of the antenna.
REFERENCES:
patent: 3597681 (1971-08-01), Huckabay
patent: 3723856 (1973-03-01), Brown
patent: 4652829 (1987-03-01), Safinya
patent: 4710713 (1987-12-01), Strikman
patent: 4717876 (1988-01-01), Masi et al.
patent: 4717877 (1988-01-01), Taicher et al.
patent: 4717878 (1988-01-01), Taicher et al.
patent: 4933638 (1990-06-01), Kenyon et al.
W. G. Clark, "Pulsed Nuclear Resonance Apparatus", The Review of Scientific Instruments, vol. 35, No. 3, (Mar. 1964).
Dobbs, in W. P. Mason and R. N. Thurston, "Physical Acoustics Principles and Methods", vol. X, (1973), title page and pp. 127-191.
E. Kartheuser, L. R. Ram Mohan, and S. Rodriguez, "Theory of Electromagnetic Generation of Acoustic Waves in Metals", Advances In Physics, vol. 35, No. 5, 423-505, (1986), contents pp. 423, 424.
A. B. Przedpeiski, "Simplify Conjugate Bilateral Matching Of Complex Impedances. A Unified Approach Provides Practical L, Pi or T Solutions With A Low-Cost Programmable Calculator", Electronic Design 5, (Mar. 5, 1978).
J. S. Belrose, "Ferromagnetic Loop Aerials For Kilometric Waves", Wireless Engineer, vol. 32 N 2 pp. 41-46 (Feb. 1955).
M. L. Buegg and G. L. Peterson, "Acoustic Ringing Effects In Pulsed Nuclear Magnetic Resonance Probes", Rev. Sci. Instrum., vol. 49, No. 8, (Aug. 8, 1978).
E. Fukushima and S. B. W. Roeder "Spurious Ringing In Pulse NMR", Journal of Magnetic Resonance, 33, 199-203 (1979).
Fukuhara Masafumi
Griffin Douglas D.
Kleinberg Robert L.
Sezginer Abdurrahman
Novack Martin M.
Pojunas Leonard W.
Schlumberger Technology Corp.
Tokar Michael J.
LandOfFree
Antenna and wear plates for borehole logging apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Antenna and wear plates for borehole logging apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Antenna and wear plates for borehole logging apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1191971