Characterization οf Sandstone Pore Network using Mercury Porosimetry, Helium Porosimetry and Scanning Electron Microscopy

Abstract

Porosity and total pore volume are fundamental properties which are vital in gaining a comprehensive insight into the structure of porous rocks. Sherwood sandstone was characterized using Mercury Intrusion Porosimetry (MIP), Helium Intrusion Porosimetry (HIP) and Scanning Electron Microscopy (SEM). The total intrusion pore volume and total porosity increased after treatment. While the bulk density decreased after treatment. The total accessible porosity was higher in the treated sample (26.95 % MIP and 30.67 % HIP) when compared with the raw (7.41 % MIP and 11.06 % HIP). The total pore volume was also larger in the treated sample (0.1538 mL/g MIP and 0.231 gcm-3 HIP) when compared with the raw (0.0775 mL/g MIP and 0.116 gcm-3 HIP). The helium intrusion had a higher result than the mercury intrusion. These results suggest helium due to its small size must have penetrated smaller and finer pores in the rock samples. The modal pore size moved from 14000 to 24000 nm. These results show that treated has more micro, meso, macro and coarse pores than the raw samples. The densities of the samples determined from HIP and MIP decreased after treatment. SEM shows the difference in surface morphology and textural properties. The raw sample was homogenous and displayed a fine grain size, while the treated has loose and less dense-packed pore space distribution. These techniques provided more insight into the assessment of porous solids.