CO2 injection into saline carbonate aquifer formations I: laboratory investigation

Abstract

Although there are a number of mathematical modeling studies for carbon dioxide (CO 2 ) injection into aquifer formations, experimental studies are limited and most studies focus on injection into sandstone reservoirs as opposed to carbonate ones. This study presents the results of computerized tomography (CT) monitored laboratory experiments to analyze permeability and porosity changes as well as to characterize relevant chemical reactions associated with injection and storage of CO 2 in carbonate formations. CT monitored experiments are designed to model fast near well bore flow and slow reservoir flows. Highly heterogeneous cores drilled from a carbonate aquifer formation located in South East Turkey were used during the experiments. Porosity changes along the core plugs and the corresponding permeability changes are reported for different CO 2 injection rates and different salt concentrations of formation water. It was observed that either a permeability increase or a permeability reduction can be obtained. The trend of change in rock properties is very case dependent because it is related to distribution of pores, brine composition and thermodynamic conditions. As the salt concentration decreases, porosity and the permeability decreases are less pronounced. Calcite deposition is mainly influenced by orientation, with horizontal flow resulting in larger calcite deposition compared to vertical flow.

Qualitative and Quantitative Changes of Carbonate Rocks Exposed to SC CO2 (Basque-Cantabrian Basin, Northern Spain)

“…of the whole system. To study these overall processes on more realistic time and space scales, numerical modelling has been successfully applied [4,7,[12][13][14][15] adjusting the models with experimental data such as those provided by this work.…”

“…One of the possible approaches is to capture CO 2 from large industrial sources and to storage it in deep geological formations [1][2][3][4]. During this process, the CO 2 is injected into a formation of high porosity and permeability (reservoir), which is overlaid by an impermeable formation (seal).…”

Qualitative and quantitative changes in detrital reservoir rocks caused by CO<sub>2</sub>–brine–rock interactions during first injection phases (Utrillas sandstones, northern Spain)

“…Deep geological storage in porous rock formations is considered the most appropriate strategy for CO 2 sequestration (Bachu, 2000;Izgec et al, 2008;Benson and Cole, 2008;Gaus, 2010) and injectivity is a key technical and economic issue for carbon capture and storage (CCS) projects (Bacci et al, 2011). The viability of the CO 2 injection depends mainly on the porosity and permeability of reservoir rocks.…”

CO2–brine–caprock interaction: Reactivity experiments on Eau Claire shale and a review of relevant literature

“…The CO 2 charged brine then becomes acidic and will react with the solid matrix, which would bring uncertainty to large-scale CO 2 storage applications. Most of the studies on CO 2 -water-rock interaction have focused on the host reservoirs (primarily sandstone or carbonate reservoirs) that store the CO 2 (Rochelle et al, 2004;Czernichowski-Lauriol et al, 2006;Izgec et al, 2008). Geochemical reactions of the caprock associated with the CO 2 sequestration have been much less studied.…”