PORE-LEVEL SIMULATION OF DENSITY DRIVEN NATURAL CONVECTION DURING CO2 GEOLOGICALSTORAGE

 

Abdelmalek Atia1, 2,*, Kamal Mohammedi2

1Univ. El-Oued , LEVRES Lab, Algeria

2 Univ. Boumerdes, LEMI Lab, Algeria

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(THEME “I”)

Abstract: Global warming is considered as a responsible to the excessive emission of greenhouse gases, one of whose main components is carbon dioxide. Saline aquifers are choice for geological storage of CO2 because of their storage potential. In almost all cases of practical interest CO2 is present on top of the liquid and it has been known that dissolution of CO2 accompanied by a small increase in the density of the aqueous phase, this configuration results the creation of negative buoyancy force that can give rise to downward density-driven natural convection and consequently greatly enhances CO2 sequestration. These phenomena are studied on mesoscopic level because of their complex analysis. In this paper, an isothermal lattice Boltzmann model (LBM) with two distribution functions is proposed to simulate density-driven natural convection in porous media packed with irregular geometry obtained by image treatment, in order to study CO2 injection at pore-level. This analysis show that after the onset of natural convection instability, the brine with a high CO2 concentration infringed into the underlying unaffected brine, which developed the interfacial area between the CO2-saturated brine and unaffected brine, and finely favored the migration of CO2 into the pores structure. This study is considered between the few pore-scales that investigating density-driven natural convection during CO2 injection projects in deep saline aquifers, whereas most existing results are focused on the macroscopic level. The results of this paper have implications also in enhanced oil/gas recovery with CO2 sequestration in aquifers.

Keywords lattice Boltzmann method, density driven, pore-scale, CO2, mass transfer ,geological storage

 

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