Experimental Analysis of the Interdependence Between Granular Dimension and Porosity in Uniformly Consolidated Sand pack Media

Abstract

Grain size constitutes a principal determinant of the petrophysical attributes of porous media, with particular relevance to porosity, the primary parameter governing fluid storage and transmissibility in petroleum reservoirs. This study systematically examined the grain-size porosity relationship in laboratory-fabricated consolidated sandpacks intended as analogues for reservoir simulation. Six discrete silica sand fractions of 0.125, 0.175, 0.250, 0.325, 0.455, and 1.500 mm were blended with Ordinary Portland Cement at an 80:20 sand-to-cement ratio and distilled water, then processed via standardized mixing, compaction, molding, and a two days curing regimen to ensure mechanical robustness and dimensional uniformity. The synthesized samples were subjected to X-ray Diffraction (XRD) to ascertain mineralogical constitution and to Brunauer–Emmett–Teller (BET) analysis. Porosity was gravimetrically determined via fluid saturation, while the influence of grain size was statistically appraised through descriptive statistics, linear regression, and analysis of variance (ANOVA). XRD confirmed quartz as the predominant mineral phase, and BET revealed a mesoporous pore architecture with adequate connectivity for fluid transport studies. Porosity decreased monotonically from 13.57% at 0.125 mm to 4.36% at 1.500 mm, reflecting reduced intergranular voidage with increasing grain size. A strong inverse correlation was observed (r = −0.954; R² = 0.910), with ANOVA confirming statistical significance (F = 40.61; p = 0.0032). The regression model ϕ = 10.98 − 5.11d quantitatively describes this trend. Thus, grain size significantly controls porosity in cemented sandpacks, and the prepared specimens exhibit adequate petrophysical properties for laboratory reservoir characterization and enhanced oil recovery core flooding studies.