Characterizing sub-core hysteretic relative permeability and capillary
pressure for accurate imbibition coreflood modeling
Using x-ray tomography in coreflooding experiments allows to
characterize the sub-core, mm-scale, multiphase flow properties such as
permeability, porosity, relative permeability and capillary pressure.
This has been studied previously for CO2-brine drainage experiments and
a procedure has been developed for sub-core property estimation, showing
that their implementation in numerical models leads to accurate
predictions of experimental measurements, such as core saturation
distribution. Much less work has been conducted regarding CO2-brine
imbibition modeling. In this work we characterize hysteretic sub-core
properties using experimental data of CO2-brine imbibition coreflooding
conducted on two core samples. We adopt the approach of  for
sub-core capillary pressure modeling and that of  for relative
permeability modeling, however, we find that these are not sufficient
for accurate modeling of saturation distribution within the core. We
improve the models by considering a unique turning point and Land
trapping coefficient for each mm-scale grid block in our model and also
by calculating new imbibition characteristic relative permeability
curves based on a procedure developed in . Results show
improvements in matching experimental data.  R. Pini, and S.M.
Benson. “Capillary pressure heterogeneity and hysteresis for the
supercritical CO2/water system in a sandstone.” Advances in Water
Resources 108 (2017): 277-292.  O. Dury, U. Fischer, and R.
Schulin. “A comparison of relative nonwetting‐phase permeability
models.” Water Resources Research 35.5 (1999): 1481-1493.  E.
Anto-Darkwah, S.M. Benson, and A. Rabinovich. “An improved procedure
for sub-core property characterization using data from multiple
coreflooding experiments.” International Journal of Greenhouse Gas
Control 105 (2021): 103226.