Molecular Simulations of Gas Adsorption in Shale Systems

Molecular simulations have emerged as a powerful tool to unravel the complex interplay between gas molecules and the organic-rich nanoporous matrix of shale. By combining atomistic and coarse-grained techniques, researchers can probe adsorption equilibria, transport kinetics and mechanical responses under realistic temperature and pressure conditions. These approaches capture the influence of nanoconfinement, pore geometry and surface chemistry on the uptake of methane, carbon dioxide and mixed gases, revealing departures from classical continuum descriptions. Simulations have demonstrated that sorption‐induced swelling of kerogen alters pore size and permeability, while strong surface interactions give rise to subcontinuum flow regimes that defy Darcy’s law. Mixed‐gas studies quantify competitive adsorption and transport selectivity, informing enhanced gas recovery and CO₂ sequestration strategies. Advances in model development now accommodate realistic kerogen structures, moisture and salinity effects, and non-equilibrium flow driven by pressure gradients. Insights from molecular dynamics and Monte Carlo methods guide the interpretation of experimental data, support the design of injection protocols and refine large‐scale reservoir models. Together, these efforts deepen our mechanistic understanding of shale gas resources and underpin sustainable exploitation and carbon management in unconventional reservoirs.

Research from Nature Portfolio

Foundational work using molecular simulation and statistical mechanics has shown that continuum formulations fail to predict transport in kerogen nanopores, where strong adsorption and breakdown of hydrodynamic assumptions produce non-Darcy flow and a unified scaling of alkane permeance with molecular size. Complementary studies combining high-resolution electron microscopy and adsorption microcalorimetry have mapped the intricate nanoscale network of amorphous and graphitic domains in kerogen, revealing that once high-energy sites are occupied, pore width rather than chemistry controls low-pressure gas uptake. These results emphasise the need to incorporate nanoscale structure and energetics into predictive models of storage and recovery.

Molecular Simulations of Gas Adsorption in Shale Systems publication trend

The graph below shows the total number of articles in molecular simulations of gas adsorption in shale systems across all publications each year (not limited to Nature Index journals).

Technical terms

Kerogen: Insoluble organic matter in shale forming an ultrafine porous matrix that adsorbs hydrocarbons.

Molecular dynamics simulation: Computational method solving Newton’s equations of motion for atoms to explore dynamic behaviour at the nanoscale.

Grand canonical Monte Carlo simulation: Statistical technique sampling particle insertions and deletions to determine adsorption equilibria at fixed chemical potential.

Nanoconfinement: Restriction of fluids within pore dimensions below 100 nm, altering thermodynamic and transport properties.

Darcy’s law: Continuum relation expressing volumetric flow rate in porous media as proportional to permeability and pressure gradient and inversely proportional to fluid viscosity.

Sorption-induced swelling: Expansion of the solid matrix caused by gas adsorption, leading to changes in porosity and transport pathways.

References

1. CO2 transport through swelling organic-rich nanoporous media: Insights on gas permeability from coarse-grained pore-scale simulations. Journal of Cleaner Production (2024).
2. Selective adsorption and transport of CO2–CH4 mixture under nano-confinement. Energy (2023).
3. Subcontinuum mass transport of condensed hydrocarbons in nanoporous media. Nature Communications (2015).
4. Nanoconfined methane flow behavior through realistic organic shale matrix under displacement pressure: a molecular simulation investigation. Journal of Petroleum Exploration and Production Technology (2021).
5. Molecular Investigation of CO2/CH4 Competitive Adsorption and Confinement in Realistic Shale Kerogen. Nanomaterials (2019).
6. Effects of Moisture and Salinity on Methane Adsorption in Kerogen: A Molecular Simulation Study. Energy & Fuels (2019).
7. Adsorption based realistic molecular model of amorphous kerogen. RSC Advances (2020).
8. Kerogen nanoscale structure and CO2 adsorption in shale micropores. Scientific Reports (2021).