The pseudo 2-D relaxation model for obtaining T1–T2 relationships from 1-D T1 and T2 measurements of fluid in porous media

Abstract NMR spin-lattice ( T 1 ) and spin-spin ( T 2 ) relaxation times and their inter-relation possess information on fluid behaviour in porous media. To elicit this information we utilize the pseudo 2-D relaxation model (P2DRM), which deduces the T 1 – T 2 functional relationship from independent 1-D T 1 and T 2 measurements. Through model simulations we show empirically that the P2DRM accurately estimates T 1 – T 2 relationships even when the marginal distributions of the true joint T 1 – T 2 distribution are unknown or cannot be modeled. Estimates of the T 1 : T 2 ratio for fluid interacting with pore surfaces remain robust when the P2DRM is applied to simulations of rapidly acquired data. Therefore, the P2DRM can be useful in situations where experimental time is limited.