Influence of Carbonated Water-rock Interactions on Enhanced Oil Recovery in Carbonate Reservoirs: Experimental Investigation and Geochemical Modeling

摘要

Recently, the use of carbonated water injection has been considered for enhanced oil recovery (EOR), and it provides a great potential for reducing CO2 emissions. Both laboratory and field applications on EOR using carbonated water injection have been reported, and various mechanisms have been suggested for oil recovery. However, the interaction between the carbonated water and rock and its influence on EOR remains unclear. Therefore, the objective of this study was to evaluate the carbonated water-rock interactions through core flooding experiments and using an advective-reactive transport model. The experimental results pertaining to permeability of the core sample, and effluent pH value and calcium concentration were presented as a function of the amount of injectant. The effect of oil present in the core sample, ageing, and kind of injectant, on the interaction and oil recovery were analyzed. The results showed that calcite in the carbonate rock dissolved owing to its interaction with carbonated water; this increased the porosity, and thus, the permeability of the rock, and effluent pH value and calcium concentration also increased. The simulation results for effluent calcium concentration and pH agree well with experimental data, indicating the applicability of the model for further understanding the interactions in the carbonate reservoir.