title: Subcontinuum mass transport of condensed hydrocarbons in nanoporous media.
abstract: Although hydrocarbon production from unconventional reservoirs, the so-called shale gas, has exploded recently, reliable predictions of resource availability and extraction are missing because conventional tools fail to account for their ultra-low permeability and complexity. Here, we use molecular simulation and statistical mechanics to show that continuum description--Darcy's law--fails to predict transport in shales nanoporous matrix (kerogen). The non-Darcy behaviour arises from strong adsorption in kerogen and the breakdown of hydrodynamics at the nanoscale, which contradict the assumption of viscous flow. Despite this complexity, all permeances collapse on a master curve with an unexpected dependence on alkane length. We rationalize this non-hydrodynamic behaviour using a molecular description capturing the scaling of permeance with alkane length and density. These results, which stress the need for a change of paradigm from classical descriptions to nanofluidic transport, have implications for shale gas but more generally for transport in nanoporous media.
authors.affiliation: Department of Civil and Environmental Engineering and MultiScale Material Science for Energy and Environment UMI 3466 CNRS-MIT, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Falk
authors.affiliation: Department of Civil and Environmental Engineering and MultiScale Material Science for Energy and Environment UMI 3466 CNRS-MIT, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
authors.forename: Benoit
authors.initials: B
authors.lastname: Coasne
authors.affiliation: Department of Civil and Environmental Engineering and MultiScale Material Science for Energy and Environment UMI 3466 CNRS-MIT, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
authors.forename: Roland
authors.initials: R
authors.lastname: Pellenq
authors.affiliation: Department of Civil and Environmental Engineering and MultiScale Material Science for Energy and Environment UMI 3466 CNRS-MIT, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
authors.forename: Franz-Josef
authors.initials: FJ
authors.lastname: Ulm
authors.affiliation: Department of Civil and Environmental Engineering and MultiScale Material Science for Energy and Environment UMI 3466 CNRS-MIT, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
authors.forename: Lydéric
authors.initials: L
authors.lastname: Bocquet