(760c) Modeling of Wellbore Cement Core-Flood Experiments
AIChE Annual Meeting
Thursday, November 7, 2013 - 4:05pm to 4:30pm
We present a theoretical model of our core-flood experiments in which brine saturated with carbon dioxide (CO2) is injected through fractured core samples composed of wellbore cement mated with caprock. When exposed to the CO2-saturated brine, the cement undergoes a series of reactions that leads to the dissolution of minerals like calcium into the brine. These reactions have implications for the long-term efficacy of subsurface CO2 sequestration, because they may affect the fracture permeability and the mechanical properties of the wellbore cement. The effluent chemistry data from the experiments show that the excess calcium concentration obey a 'super-diffusive' growth. We find that a good match with experimental data can be achieved by introducing a term that represents a constant background source of calcium. Our model provides explanations for the physical origin of this source term.