Fig. 10 Distribution of water at an acceleration of 0.002 nm/ps2 and Cw = 71.43% in 5nm, 10nm, 15nm H-H pores. The hydrocarbon molecules are not shown. The result indicates that at each pore size, the peaks and troughs in the velocity profiles correspond to the local density of each of the phases.

4.2 Fluid Transport in P-H Nanopores

In the previous section, we reviewed transport of water and hydrocarbon in H-H pore systems where water bridges are largely absent except under some specific conditions. In this section, we present the corresponding results for P-H pores where water bridges are prevalent across multiple pore sizes and water concentrations.
The water and hydrocarbon velocity profiles for 54 NEMD simulations in P-H nanopore are provided in Figs. S6-7 in Supporting Information. In this section, we only analyze a few representative hydrocarbon-water velocity profiles in P-H nanopores and address the effects of pore size, water concentration and electric field (the effects of acceleration are provided in Supporting Information).
Effect of Pore size
Fig.11 shows the water (Fig.11a) and hydrocarbon (Fig.11b) velocity profiles at an acceleration and water concentration of 0.002 nm/ps2 and 71.43% respectively in different P-H nanopore sizes. Water and hydrocarbon velocities increase with an increase of pore size which is in agreement with Liu et al.41. Additionally, water and hydrocarbon velocity profiles are parabolic in the 5 nm P-H nanopore and show flatter profiles for the 10nm and 15nm pores with increasing distance from the pore walls and the accompanying decrease in fluid-pore wall interactions.