Determination of pores properties in rocks by means of helium-3 NMR: A case study of oil-bearing arkosic conglomerate from North belt of crude oil, Republic of Cuba

The developments of helium-3 nuclear magnetic resonance (NMR) technique to assess porous media properties such as porosity and pore size distribution (PSD) are reported. The method is suitable for use to characterize unconventional extra-heavy oil reservoirs, has a potential in application to tight shales and other unconventional formations, and has several advantages over conventional water NMR. It is based on He-3 nuclear magnetic relaxation measurements for different pore loadings and inverse Laplace transform of the data. The relation between different pore types as well as their mean radii are found within the models of spherical, cylindrical and planar pores. The method was applied to study porosity and PSD of rock samples acquired at the North belt of crude oil, Republic of Cuba, the unconventional formation known for its complexity. The obtained pore sizes and porosities are in a good agreement with conventional methods which validates the proposed He-3 NMR approach for porous media studies. Advantages of the He-3 liquid and gas as probes are discussed.

Automated summary

The developments of helium-3 nuclear magnetic resonance (NMR) technique for assessing porous media properties have been reported. This method is suitable for unconventional extra-heavy oil reservoirs and has potential applications in tight shales and other unconventional formations. It has advantages over conventional water NMR and is based on He-3 nuclear magnetic relaxation measurements and inverse Laplace transform. The study found the relation between different pore types and their mean radii using models of spherical, cylindrical, and planar pores.