Ground‐Truth Validation of T2 ${T}_{2}$ Estimates From Steady‐State Surface NMR

Abstract

Steady‐state sequences are a new protocol for surface nuclear magnetic resonance (NMR), that can yield high quality data in a short time. In addition to faster acquisition, steady‐state surface NMR purports to measure the transverse relaxation time , which is correlated with hydrogeological parameters like pore‐size. This is in contrast to the effective transverse relaxation time associated with standard single pulse measurements, which may or may not be correlated with pore‐size. While previous studies suggest that steady‐state measurements have enhanced sensitivity to , a ground‐truth validation has not yet been done. We compare steady‐state surface NMR results against borehole NMR logs at four locations. For relaxation regimes of > 10 ms, profiles from steady‐state data are in excellent agreement with borehole measurements, provided the assumption of homogeneous horizontal layers is valid. Even in more complex geological environments, steady‐state surface NMR delivers representative estimates of .