We report proton. longitudinal relaxation (T1) measurements on water-saturated samples of Western Tight Sas Sand Core and artifioal porous materials. The artificial samples, with well-characterized and nearly uniform pore structure, serve as a calibration standard for preliminary-efforts at inverting the Nuclear Magnetic Resonance relaxation data on the Gas Sand core samples to obtain a distribution of pore surface-to-volume ratios. The distributions obtained show good to excellent agreement with those obtained by mercury porosimetry on the same samples. Various possible effects are discussed, which could account for the discrepancies observed.