Abstract:
Proton nuclear magnetic spin-spin relaxation time distributions (Tz distributions) for a water-saturated cylinder
of sandstone (radius 6.5 cm and length 17.55 em) have been studied as a function of drying time. By freezing
the sample to -13.7 °C, a proportionality constant of 38.8 µs/nm was determined that can be used to relate
pore size to T₂. The results show external water cannot enter some intermediate sized pores of 400 nm diameter;
however, these pores are available to water that has been frozen and allowed to thaw. On drying from saturation,
water loss commences immediately from pores of the order of 1000 nrn and greater and there is a lag period
of 51 h before the smaller pores begin to drain. On freezing and then thawing, intermediate sized pores are
filled because the large pores are blocked by ice.
