Solid-like Component in the Spin-Spin NMR-Relaxation of Heavy Oils

摘要

The study of row heavy oil samples from Tatarstan and Vietnam oil wells was done by solid-echo nuclear magnetic resonance (NMR) technique on the hydrogen nuclei. For the first time in the oil study, the component with short spin-spin relaxation time (T2s=9.8-31.2 ms) and free induction decay (FID) shape similar to a solid one was detected for all oil samples. Density ho, "zero" viscosity eta_0, asphaltene content andsolid partPSof 1H NMR signal were measured for whole row oil samples. The correlation between the part PS of 1H NMR signal and oil density r was found for samples of Tatarstan oil, by the other hand, data for samples of Vietnam oil did not show the correlation. No correlation dependences of the part PS of 1H NMR signal and "zero" viscosity eta_0 from asphaltene amount for whole row of oil samples were confirmed, thatindicatesother crystalline supramolecular structures (more probably, crystalline paraffin) existence in the oil. As a main result, the correlation between oil viscosity and the amount of the solid-like structures in it was found. The significant differences of the solid-echo signal shapes and spin-spin relaxation times of the solid-like structures were obtained for the different oil samples, that demands additional studies.