Theory of surface nuclear magnetic resonance with applications to geophysical imaging problems

Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics

Volumn 62, Issue 1 B, 2000, Pages 1290-1312

  Weichman, Peter B ^a   Lavely, Eugene M ^a   Ritzwoller, Michael H ^b  

^a Blackhawk Golden   (United States)

^b UNIVERSITY OF COLORADO   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; GEOPHYSICS; NUCLEAR MAGNETIC RESONANCE;

RESPONSE VOLTAGE;

MAGNETIC RESONANCE IMAGING;

EID: 0034227094     PISSN: 1063651X     EISSN: None     Source Type: Journal    
DOI: 10.1103/PhysRevE.62.1290     Document Type: Article

References (29)

1. See, e.g., A. Abragam, Principles of Nuclear Magnetism (Oxford University Press, New York, 1983).
2. In medical applications the surface NMR technique discussed here is known as "rotating frame imaging" or "nutation imaging" using a surface pickup coil [see, e.g., D. I. Hoult, J. Magn. Reson. 33, 183 (1978)]. The technique still requires a laboratory generated static field.
3. Invasive borehole NMR tools have been in use in the oil industry for some time. See, e.g., R. L. Kleinberg, The Industrial Physicist 2 (2), 18 (1996). However, due either to geometric limitations of the transmitter loop or to the fact that the tool generates its own static field, it is sensitive to oil or water only to within a fraction of a meter of the borehole into which it is lowered.
4. See, e.g., D. V. Trushkin, O. A. Shushakov, and A. V. Legchenko, Geophys. Prospect. 43, 623 (1995).
5. A. V. Legchenko and O. A. Shushakov, Geophys. J. 63, 75 (1998).
6. M. Goldman, B. Rabinovich, M. Rabinovich, D. Gilad, I. Gev, and M. Schirov, J. Appl. Geophys. 31, 27 (1994).
7. A preliminary version of our results has appeared in P. B. Weichman, E. M. Lavely, and M. H. Ritzwoller, Phys. Rev. Lett. 82, 4102 (1999), and has also been featured on the Physical Review Focus website, Dowsing with Nuclear Magnetic Resonance, http://focus.aps.org/v3/st27.html, May 17, 1999.
8. A preliminary version of our results has appeared in P. B. Weichman, E. M. Lavely, and M. H. Ritzwoller, Phys. Rev. Lett. 82, 4102 (1999), and has also been featured on the Physical Review Focus website, Dowsing with Nuclear Magnetic Resonance, http://focus.aps.org/v3/st27.html, May 17, 1999.
9. Finite skin depth effects, computable as special cases of the general theory we present, have been considered previously in terms of dissipation and resulting NMR voltage phase shifts in solid state [see, e.g., M. D. Harpen, Phys. Med. Biol. 33, 597 (1988)] and biological systems [see, e.g., P. A. Bottomely and E. R. Andrew, ibid. 23, 630 (1978)].
10. Finite skin depth effects, computable as special cases of the general theory we present, have been considered previously in terms of dissipation and resulting NMR voltage phase shifts in solid state [see, e.g., M. D. Harpen, Phys. Med. Biol. 33, 597 (1988)] and biological systems [see, e.g., P. A. Bottomely and E. R. Andrew, ibid. 23, 630 (1978)].
11. See, e.g., K. R. Foster, H. P. Schwan, and M. A. Stuchly, Crit. Rev. Biomed. Eng. 17, 25 (1989).
12. P.-M. L. Robitaille, A. Kangarlu, and A. M. Abduljalil, J. Comput. Assist. Tomogr. 23, 845 (1999).
13. A. M. Abduljalil and P.-M. L. Robitaille, J. Comput. Assist. Tomogr. 23, 832 (1999).
14. A. Kangarlu, B. A. Baertlein, R. Lee, T. Ibrahim, L. Yang, A. M. Abduljalil, and P.-M. L. Robitaille, J. Comput. Assist. Tomogr. 23, 821 (1999).
15. See, e.g., J. M. Jin, J. Chen, W. C. Chew, H. Gan, R. L. Magin, and P. J. Dimbylow, Phys. Med. Biol. 41, 2719 (1996).
16. J. D. Jackson, Classical Electrodynamics, 2nd ed. (Wiley, New York, 1975).
17. 2 for fluids in geophysical porous materials are discussed in R. L. Kleinberg, W. E. Kenyon, and P. P. Mitra, J. Magn. Reson. A 108, 206 (1994), and references therein.
18. This is especially the case when the transmitter loop is also used as the receiver loop. The NMR signal induced in the transmitter loop can then only be measured after shut off of the transmitter source current.
19. 0 (appropriate to the case of coincident transmitter and receiver coils). Since they are considering high conductivity soils with skin depth on the order of 10 m and modeling water content down to nearly 100 m, conductivity effects are clearly dominant. Although the formula they use then contains the correct dynamics (2.2), of the nuclear spins, it misses the equally important memory effect, and the imaginary part of the response contained in (2.21).
20. 0 (appropriate to the case of coincident transmitter and receiver coils). Since they are considering high conductivity soils with skin depth on the order of 10 m and modeling water content down to nearly 100 m, conductivity effects are clearly dominant. Although the formula they use then contains the correct dynamics (2.2), of the nuclear spins, it misses the equally important memory effect, and the imaginary part of the response contained in (2.21).
21. Inclusion of a finite ∈′ would cure the apparently unphysical instantaneous arrival of the exponential tail of the diffusing front at the point r. The leading edge would then only arrive after a delay time r/∈′ c much shorter than the time scales of interest in this work.
22. D. R. Lun, P. B. Weichman, M. H. Ritzwoller, and E. M. Lavely (unpublished).
23. See, e.g., A. A. Kaufman, Geophysical Field Theory and Method (Academic Press, New York, 1992), Part A, p. 412.
24. D. I. Hoult and R. E. Richards, J. Magn. Reson. 24, 71 (1976).
25. See, e.g., J. M. Hendrickx, T. Yao, A. Kearns, P. Hoekstra, R. J. Blohm, M. W. Blohm, P. B. Weichman and E. M. Lavely, DOE Report No. DE-FG07-96ER14732, 1999 (unpublished).
26. L) be defined continuously for all other positions and frequencies. This has the disadvantage of requiring global, rather than just local, knowledge of the phase, but succeeds in removing artifactual discontinuous changes in the phase and the polarization vector.
27. The quadrature component of the NMR voltage is indeed measured, though with poor accuracy, by the instruments currently in use for ground-water imaging, and is found to vary substantially from site to site (Mark W. Blohm, private communication). However, prior to the present work, there has been no attempt to analyze this part of the signal either to correlate it with ground conductivity or for imaging purposes.
28. 1 involves the application of a 180°, pause, 90° pulse sequence. However this requires a uniform tipping field, which is unavailable in both geophysical borehole and geophysical surface NMR contexts.
29. See, e.g., R. L. Parker, Geophysical Inverse Theory (Princeton University Press, Princeton, NJ, 1994).