es8b00251_si_001.pdf (3.08 MB)
Effect of CO2 Phase States and Flow Rate on Salt Precipitation in Shale CaprocksA Microfluidic Study
journal contribution
posted on 2018-04-23, 20:19 authored by Mohammad Nooraiepour, Hossein Fazeli, Rohaldin Miri, Helge HellevangFracture
networks inside the caprock for CO2 storage
reservoirs may serve as leakage pathways. Fluid flow through fractured
caprocks and bypass conduits, however, can be restrained or diminished
by mineral precipitations. This study investigates precipitation of
salt crystals in an artificial fracture network as a function of pressure–temperature
conditions and CO2 phase states. The impact of CO2 flow rate on salt precipitation was also studied. The primary research
objective was to examine whether salt precipitation can block potential
CO2 leakage pathways. In this study, we developed a novel
microfluidic high-pressure high-temperature vessel to house geomaterial
micromodels. A fracture network was laser-scribed on the organic-rich
shales of the Draupne Formation, the primary caprock for the Smeaheia
CO2 storage in Norway. Experimental observations demonstrated
that CO2 phase states influence the magnitude, distribution,
and precipitation patterns of salt accumulations. The CO2 phase states also affect the relationship between injection rate
and extent of precipitated salts due to differences in solubility
of water in CO2 and density of different CO2 phases. Injection of gaseous CO2 resulted in higher salt
precipitation compared to liquid and supercritical CO2.
It is shown that micrometer-sized halite crystals have the potential
to partially or entirely clog fracture apertures.