1887

Abstract

Summary

Low-field NMR relaxation of the fluids inside the porous rock is the result of bulk and surface relaxation of the protons inside the pore fluid. Bulk relaxation is a fluid property when the solid-fluid interaction is minimized. Surface relaxation is the result of the solid-fluid interaction related to mineral properties. Thus, longitudinal, T1, and transverse, T2, relaxation times should in principle be similar. However, microscopic magnetic gradients related to minerals can shorten T2 as compared to T1 provided the saturating fluid has high affinity to the solid. We consequently find that the T1/T2 ratio can quantify the affinity between the rock and wetting pore fluid. The affinity is a measure directly linked to wettability.

In order to investigate the T2-shortening, we performed T1-T2 NMR experiments on different samples of chalk, Berea sandstone, and chloritic greensand, saturated either with water, oil or oil/water at irreducible water saturation. The T1/T2 ratio obtained from T1-T2 maps reflects the T2-shortening. We compare the T1/T2 ratio for the same type of rock, saturated with different fluids. The chalk shows high affinity for water, Berea sandstone has no clear preference for oil and water whereas chloritic greensand shows different behavior for small and large pores.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.201600885
2016-05-30
2024-04-19
Loading full text...

Full text loading...

References

  1. Bæk, M.
    , 2014, Oil and Gas Production in Denmark and Subsoil Use, Danish Energy Agency, ISBN: www-978-87-93071-71-1, ISSN: 1904–0253.
    [Google Scholar]
  2. D'Agostino, C., Mitchell, J., Mantle, MichaelD., and Gladden, L.F.
    , 2014, Interpretation of NMR Relaxation as a Tool for Characterising the Adsorption Strength of Liquids inside Porous Materials, Chemistry European Journal, 20(40), 13009–13015.
    [Google Scholar]
  3. Dunn, K., Bergman, D.J. and LaTorraca, G.A.
    , 2002, Nuclear Magnetic Resonance-Petrophysical and Logging Application, New York, Handbook of Geophysical Exploration, Pergamon Press.
  4. Freedman, R., Heaton, N., Flaum, M., Hirasaki, G.J., Flaum, C., and Hürlimann, M.D.
    , 2003, Wettability, saturation, and viscosity using NMR measurements: SPE Journal, 8(12), 317–324.
    [Google Scholar]
  5. Hürlimann, M.D., Freedman, R., Venkataramanan, L., Flaum, C., Flaum, M., Hirasaki, G.J.
    , 2003, Diffusion-relaxation distribution functions of sedimentary rocks in different saturation states, Magnetic Resonance Imaging, 21(3–4), 305–310.
    [Google Scholar]
  6. Hsu, W., Li, X., and Flumerfelt, R.W.
    , 1992, Wettability of Porous Media by NMR Relaxation Methods. Washington, DC, SPE24761.
  7. Howard, J.
    , 1998, Quantitative estimates of porous media wettability from proton NMR measurements, Magnetic Resonance Imaging, 16(5), 529–533.
    [Google Scholar]
  8. Kleinberg, R.L., Farooqui, S.A., and Horsfield, M.A.
    , 1993, T1/T2 Ratio and Frequency Dependence of NMR Relaxation in Porous Sedimentary Rocks, Colloid Interface Science, 158, 195–198.
    [Google Scholar]
  9. McDonald, P.J., Korb, J.-P., Mitchell, J. and MonteilhetL.
    , 2005, Surface relaxation and chemical exchange in hydrating cement pastes: A two-dimensional NMR relaxation study, Physics Review, E 72, 011409.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609.201600885
Loading
/content/papers/10.3997/2214-4609.201600885
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error