Pore size distribution from NMR and image based methods: A comparative study

In a previous work, we showed how to obtain the surface relaxivity as a function of pore size. In the present work, we take a step further and introduce a formulation that uses this surface relaxivity function to convert a T-2 distribution into a pore size distribution. We then compare the pore size distribution obtained with the aid of this formulation with the pore size distribution obtained with the aid of other image and non-image-based methodologies for three case studies. Particularly, we compare the pore size distribution obtained with the aid of the introduced formulation with the pore size distribution obtained from the uniform surface relaxivity hypothesis, using the uniform value obtained experimentally. The comparisons indicate that, at least for the studied cases, the use of the surface relaxivity function instead of the uniform value leads to a more accurate pore size distribution, indicating thus that the varying surface relaxivity and the formulation introduced here have the potential to improve the estimate of all other related subsequent petrophysical deliverables.