CO2 Injection into Saline Carbonate Aquifer Formations II: Comparison of Numerical Simulations to Experiments

Abstract

Sequestration of carbon dioxide in geological formations is an alternative way of managing extra carbon. Although there are a number of mathematical modeling studies related to this subject, experimental studies are limited and most studies focus on injection into sandstone reservoirs as opposed to carbonate ones. This study describes a fully coupled geochemical compositional equation-of-state compositional simulator (STARS) for the simulation of CO 2 storage in saline aquifers. STARS models physical phenomena including (1) thermodynamics of sub-and supercritical CO 2 , and PVT properties of mixtures of CO 2 with other fluids, including (saline) water; (2) fluid mechanics of single and multiphase flow when CO 2 is injected into aquifers; (3) coupled hydrochemical effects due to interactions between CO 2 , reservoir fluids, and primary mineral assemblages; and (4) coupled hydromechanical effects, such as porosity and permeability change due to the aforementioned blocking of pores by carbonate particles and increased fluid pressures from CO 2 injection. Matching computerized tomography monitored laboratory experiments showed the uses of the simulation model. In the simulations dissolution and deposition of calcite as well as adsorption of CO 2 that showed the migration of CO 2 and the dissociation of CO 2 into HCO 3 and its subsequent conversion into carbonate minerals were considered. It was observed that solubility and hydrodynamic storage of CO 2 is larger compared to mineral trapping.

CO2 injection into saline carbonate aquifer formations I: laboratory investigation

“…15. The details of the numerical model can be found elsewhere (Izgec et al 2007). In order to show that the model could be used to simulate the experiments a synthetic case similar to experiments 1 was used.…”

CO2-induced dissolution of low permeability carbonates. Part II: Numerical modeling of experiments

“…CO 2 dissolution into reservoir fluids during EOR flooding mildly acidifies the resident brines and causes carbonate minerals to dissolve sometimes resulting in the formation of highly porous and conductive channels (often referred to in the petroleum acidizing literature as ''wormholes,'' e.g., [6]). Despite the large number of experimental and numerical studies devoted to understanding permeability evolution in carbonate rocks, only a few of them have made direct, comprehensive comparisons between predictive models and experimental data (e.g., [18][19]). The result is a lack of proper quantitative calibration, which limits the application of essential features of chemical fluid-rock interactions at laboratory or reservoir scales.…”

Numerical Investigation into the Impact of CO2-Water-Rock Interactions on CO2 Injectivity at the Shenhua CCS Demonstration Project, China

“…Reactive transport modeling has been previously used to investigate geochemical reactions and their effects on permeability and porosity evolution [14,15,[23][24][25][26]. André et al [14] simulated CO 2 storage in the carbonate-rich Dogger aquifer in the Paris Basin (France) using the reactive transport simulator TOUGHREACT.…”

“…Some studies [25,26] also reported that geochemical reactions dissolved the host rock increasing porosity and permeability thereby affecting fluid flow through reactive transport modeling. On the other hand, Izgec et al [23] found that CO 2 injection into carbonate aquifers simulated using CMG's STARS could result in permeability reduction as well as improvement depending on the balance between mineral dissolution and precipitation. Furthermore, Sbai and Azaroual [24] found that CO 2 injection could in some circumstances cause particulates to clog reservoir pores leading to a permeability reduction and injectivity decline near the injection well.…”