Competition among flow, dissolution, and precipitation in porous media

Abstract

A theoretical and experimental study has been carried out on flow, dissolution, and precipitation in porous media. Flow experiments were performed on linear carbonate cores using acidic ferric chloride solutions. Dissolution of the carbonate by the acid causes an increase in the solution pH, thereby precipitating ferric hydroxide. This precipitate plugs up the pore throats in the medium and increases the resistance to fluid flow. Fluctuations in the permeability ratio were observed during core flood experiments, confirming the competition between channel formation due to dissolution and pore plugging due to precipitation. The evolution of the pore structure was characterized by Wood's metal castings.A network model has also been developed to describe flow and reaction in porous media. The model was used to simulate the ferric chloride system, and pressure oscillations predicted by the model show identical trends to those observed experimentally. Additionally, the evolution of pores in the network were graphically represented.

Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures

“…This dissolution increases the effective porosity slightly. In this study, we have assumed that changes in effective porosity due to precipitation/dissolution affect the permeability of the medium, in agreement with previous research (Olivella et al, 1996(Olivella et al, , 2011Rege and Fogler, 1989). As a first approach, we have assumed that the relationship between permeability and active porosity for rock salt follows a power law, similar to the relationship between porosity and permeability within the backfill during compaction (Blanco-Martín et al, 2015a).…”

“…Halite solubility constraints introduce a new phase into the flow sub-problem, so that in addition to the gas and liquid phases, a solid phase is also possible. As shown in the literature, the presence of a solid phase affects porosity and permeability (Olivella et al, 1996(Olivella et al, , 2011Rege and Fogler, 1989), and therefore may have an impact on the flow barrier role of the host rock and the backfill. To evaluate these impacts, we have performed coupled simulations of a generic salt repository accounting for these effects, and we have compared the results with simulations in which halite solubility constraints are neglected.…”

Application of neutron radiography to image flow phenomena in porous media

“…During the presence of both dissolution and precipitation phenomena, the overall conductivity of the porous medium experiences transient oscillations owing to the competing and opposite effects of both the dissolution and subsequent precipitation phenomena. The transient effects are detailed by Rege and Fogler (1989).…”

Fractal Characteristics and Scaling of the Drying Front in Porous Media: A Pore Network Study

“…Blunt et al [9] presented a detailed review. Lately they have been used to study processes in porous media where heat, [10] mass transfer, [11][12][13][14] and reaction [15][16][17] are important. Pore networks studies that examine drying=evaporation in porous media are discussed in the remaining of the section.…”