Therefore, the transverse relaxation time
, [T.sub.2], is directly proportional to the size of the pores.
where [T.sub.2] means the transverse relaxation time
of the porous fluid collected by Carr-Purcell-Meiboom-GiU (CPMG) sequence, [T.sub.2F] is the free relaxation time, [T.sub.2F] is the surface relaxation time, and [T.sub.2F] is the diffusion relaxation time.
The Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence was used to determine the transverse relaxation time
[T.sub.2] of samples.
The transverse relaxation time
[T.sub.2] is related to the properties of fluid itself and the interaction between fluid and rock pore surface, and so on.
The bandwidth depends on the transverse relaxation time
[[GAMMA].sub.2], as evident from (4) and (6).
Values as high as 140 h, potentially limited by magnetic field gradients, have been observed for the transverse relaxation time
T2 in sealed low pressure cells .
Low-field nuclear magnetic resonance (LF-NMR) is sensitive to water in the pores of rock and soil, and the curves of transverse relaxation time
[T.sub.2] obtained by LF-NMR were used to study the pore size distribution and the characteristics of micro-structural change.
In addition, the effect of water saturation degree on transverse relaxation time
([T.sub.2]) distribution was investigated.