A pore-throat segmentation method based on local hydraulic resistance
equivalence for pore-network modeling
Abstract
The pore network is an approximate representation of the void space of
porous materials such as rocks and soil via pores (corresponding to
large cavities) and throats (narrow constrictions). During extraction of
networks from real void space, ambiguous definitions of pores and
throats may cause significant errors in predictions of
single/multi-phase transport properties. Meanwhile, the pore-throat
segmentation needs to exclude non-physical parameters as much as
possible. In this work, we propose a pore-throat segmentation method
based on local hydraulic resistance equivalence between the real space
and the pore-throat geometry. The pore-throat boundary is locally
determined at the position where the pore network preserves the
hydraulic resistance of the real space most. This local segmentation
method ensures better equivalency between extracted pore-network and
real pore space without any impirical and non-physical parameters. After
validations of accuracy and reliability by standard benchmarks, this
method is appled to real porous materials including spherical pack,
sandpack, sandstone, and carbonate. The absolute permeability and
relative permeability predicted by the new pore-network model (PNM)
agree well with the experimental data and the direct simulation results.
The proposed method improves the accuracy of PNM predictions
significantly with only slight increases of computational costs. This
local pore-throat segementation method may enhance capability of PNM and
extend PNM to more complicated cases.