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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

MOLECULAR SIMULATION OF WATER ADSORPTION IN SHALE KEROGEN SPHERICAL NANO-PORES

Get access (open in a dialog) DOI: 10.1615/IHTC16.mtr.022423
pages 5749-5756

Аннотация

Hydraulic fracturing is an important technique in the exploration of shale gas and used widely, water could displace the methane stored in the shale nanopores and might influence the physical properties of shale. Complex shale pore surface with different material composition, different geometry, it's necessary to consider how the water adsorbs on the surface of shale nanopores. All the shale matrix pores are in nanoscale, in which the organic kerogen pore radii are mostly less than 10 nm. The nanoscale kerogen pores provide huge specific surface area for shale reservoir. Comparing with the methane fluid stored in shale kerogen organic pores, water shows stronger adsorption affinity because of its intermolecular interaction with the pore surfaces. Based on a novel molecular simulation workflow, the kerogen pores are constructed using Molecular Dynamics under typical reservoir condition (up to 20 MPa). In the confined space of shale nanopores, the pore surface curvature has important implications for fluid phase change, the theory for phase change in macro scale is no longer suitable for the water phase change in shale nanopore. The surface of confined space has strong effect on fluid density fluctuations, and in nanoscale the fluctuation of fluid surface tension weakens the stability of the condensate liquid, we use Molecular Dynamics and Monte Carlo methods to model the nanoscale water/kerogen system and research the water adsorption and phase change in shale nanopores.