The two-phase displacement process occurring within the pores of a porous medium fundamentally represents the continuum-scale behavior of immiscible flow. Therefore, investigating pore-scale displacement patterns and flow morphologies provides deeper insight into the intrinsic mechanisms governing two-phase flow in geological formations. Unlike most previous studies, which mainly focused on single-factor effects, such as wettability or interfacial tension, this study develops a multi-parameter, coupled dynamic-capturing simulation framework that integrates the Navier–Stokes equations with the phase-field method. This framework systematically incorporates wettability, interfacial tension, pore-structure heterogeneity (disorder number λ), and surface roughness (root mean square) to elucidate their synergistic effects on immiscible displacement. Here, λ denotes a scalar heterogeneity index that sets the half-width of the uniform sphere-radius distribution in our model, i.e., r∈[(1−λ) r¯,(1+λ) r¯]; under this construction, the coefficient of variation satisfies COV = std(r)/r¯=λ/3, so larger λ monotonically increases geometric disorder [Blunt et al., “Detailed physics, predictive capabilities and macroscopic consequences for pore-network models of multiphase flow,” Adv. Water Resour. 25(8), 1069–1089 (2002) and R. Holtzman, “Effects of pore-scale disorder on fluid displacement in partially-wettable porous media,” Sci. Rep. 6(1), 36221 (2016)]. The simulations reveal the formation and evolution mechanisms of three residual oil forms: isolated oil droplets, oil columns, and clustered oil blobs, each arising from distinct structural configurations. This work provides a morphology-resolved, multi-parameter pore-scale analysis that integrates wettability, interfacial tension, quantified heterogeneity (λ), and surface roughness and highlights the dynamic fragmentation of clustered oil blobs. The findings provide a scientific basis for improving oil recovery in highly heterogeneous reservoirs.

In this study, a pore-scale simulation method is applied to quantitatively study the variation of solute dilution through porous media with different cementation degrees and explore the corresponding mechanisms. The study results indicated that the cementation degrees of the solid grains had a significant effect on the solute dilution process and that the influence was very complicated. The complexity was manifested in that the effect of rising cementation degree on the solute dilution process would be different or even completely opposite in the porous media in which the solid grains cement slightly with that in porous media with a higher cementation degree. For example, for the porous media in which the solid grains were slightly cemented (the percentage of the cemented solid grains is less than 40%), the dilution effects became enhanced with the increase of cementation degree. Then, after increased to about 55%, the dilution effect was obviously weakened, and the solute was in an incomplete dilution state for a long period of time. In addition, this study found that the properties of the flow fields may vary greatly in porous media with different cementation degrees and that those differences in the flow fields resulted in the distinct behavior of the solute dilution. It is interesting to note that a more heterogeneous flow field had not necessarily led to the enhancement of the dilution process.