Mesoscopic modeling of heptane: A surface tension calculation

TL;DR

This paper develops a mesoscopic mDPD model for heptane, validated against experimental and MD data, offering accurate predictions of bulk properties and surface tension, with significantly improved computational efficiency for flow simulations in porous rocks.

Contribution

The paper introduces a calibrated, atomistically-validated mDPD model for heptane that is faster and accurate, enabling better flow modeling in geotechnical applications.

Findings

Accurately predicts pressure-density relation of heptane.

Successfully reproduces surface tension measurements.

Model is three orders of magnitude faster than MD simulations.

Abstract

Accurate and efficient flow models for hydrocarbons are important in the development of enhanced geotechnical engineering for energy source recovery and carbon capture & storage in low-porosity, low-permeability rock formations. This work reports an atomistically-validated, mesoscopic model for heptane based on a many-body dissipative particle dynamics (mDPD) method. In this model, each heptane molecule is coarse-grained in one mDPD bead and the mDPD model parameters are calibrated with a rigorous approach using reference data, including experimental measurements and/or molecular dynamics (MD) simulations. Results show that this mDPD model accurately predicts the bulk pressure-density relation of heptane and surface tension. Notice that our approach can be used to calibrate the mDPD model for other hydrocarbons as well, though heptane is chosen as a representative source fluid for its abundance in source rocks. Further, our timing test indicates that the mDPD model is three orders of magnitude faster than its MD counterpart for simulations of bulk heptane in equivalent volumes. Overall, this work serves as a key prerequisite for the development of accurate and efficient mesoscale models for the flow of hydrocarbons confined in mesoporous rock formations.