Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Synchrotron-based pore-network modeling of two-phase flow in Nubian
  Sandstone and implications for capillary trapping of carbon dioxide   Depleted oil fields in the Gulf of Suez (Egypt) can serve as geothermal
reservoirs for power generation using a CO2-Plume Geothermal (CPG) system,
while geologically sequestering CO2. This entails the injection of a
substantial amount of CO2 into the highly permeable brine-saturated Nubian
Sandstone. Numerical models of two-phase flow processes are indispensable for
predicting the CO2-plume migration at a representative geological scale. Such
models require reliable constitutive relationships, including relative
permeability and capillary pressure curves. In this study, quasi-static
pore-network modelling has been used to simulate the equilibrium positions of
fluid-fluid interfaces, and thus determine the capillary pressure and relative
permeability curves. Three-dimensional images with a voxel size of 0.65 micro
m3 of a Nubian Sandstone rock sample have been obtained using Synchrotron
Radiation X-ray Tomographic Microscopy. From the images, topological properties
of pores/throats were constructed. Using a pore-network model, we performed a
sequential primary drainage-main imbibition cycle of quasi-static invasion in
order to quantify (1) the CO2 and brine relative permeability curves, (2) the
effect of initial wetting-phase saturation (i.e. the saturation at the point of
reversal from drainage to imbibition) on the residual-trapping potential, and
(3) study the relative permeability-saturation hysteresis. The results improve
our understanding of the potential magnitude of capillary trapping in Nubian
Sandstone, essential for future field-scale simulations. Further, an initial
basin-scale assessment of CO2 storage capacity, which incorporates capillary
trapping, yields a range of 14-49 GtCO2 in Nubian Sandstone, Gulf of Suez
Basin.

2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin