Penetration and Displacement Behavior of N(2) in Porous Interlayer Structures Containing Water/Salt Component by Molecular Dynamics Simulation

The penetration and displacement behavior of N(2) molecules in porous interlayer structures containing a water/salt component with porosities of 4.29%, 4.73%, 5.17%, 7.22%, and 11.38% were explored using molecular dynamics simulations. The results demonstrated that the large porosity of the interlayer structures effectively enhanced the permeation and diffusion characteristics of N(2). The water and salt in the interlayer structures were displaced during the injection of N(2) in the porosity sequence of 4.29% < 4.73% < 5.17% < 7.22% < 11.38%. The high permeance of 7.12 × 10(−6) indicated that the interlayer structures with a porosity of 11.38% have better movability. The strong interaction of approximately 15 kcal/mol between N(2) and H(2)O had a positive effect on the diffusion of N(2) and the displacement of H(2)O before it reached a stable equilibrium state. The distribution of N(2) in porous interlayer structures and the relationship between the logarithm of permeability and breakthrough pressure were presented. This work highlighted the effects of porosity on the permeability and diffusion of N(2)/H(2)O in the interlayer, thus providing theoretical guidance for the development of petroleum resources.