Experimental Research on the Gas Hydrate Based on T2 and T1–T2 Low Field NMR Technique

Abstract

Summary We conducted the T2 and T1–T2 low field NMR experiment to detect the formation and dissociation process of the methane gas hydrate in sedimentary rocks and artificial cores. Based on our investigations. (1)The gas hydrate forms preferentially in large pores and it is easier for the gas hydrate to reach the equilibrium state than for samples with small pore diameter and grain size. (2)The gas hydrate volume is positively correlated with the porosity, but there is no obvious relationship between the gas hydrate saturation and the porosity. (3)The spectrum distributions move towards the fast relaxation domain with the growth of gas hydrate, because the generated gas hydrate occupies the large pore and accelerate the relaxation rate. (4) It is easier for the gas hydrate in the sample of high porosity and large pore size to dissociate than that in the sample of low porosity and small pore size. (5) T1–T2 spectrum gives new perspective of the porous media, which helps us to discriminate complex components that cannot be interpreted only by the T2 spectrum.