Numerical Modeling of Nanoparticle Injection and Ionic Removal for Cementitious Materials

Recently, nanoparticle injection technology has been developed for the remediating and repairing cracks in wellbore systems that can be used for underground CO2 storage. The repair technology can seal the cracks and prevent the CO2 from leaking. In this work, a numerical model was developed to simulate the coupling effects among various ions in pore solution of well cement used in underground wellbore systems as well as the injection of nanoparticles during the leak repairing process in boreholes. Two main governing equations, the Nernst-Planck and Poisson's equations, were used to derive the transport and migration of ions driven by external current in the pore solution. The governing equations were solved using the finite element method based on the multiphysics object-oriented simulation environment (MOOSE) framework. The concentration profiles of the ions in well cement were obtained at different times and depths. The nanoparticle injection process was simulated with the appearance of five different ions in the solution of well cement. The effect of the external current for penetration of nanoparticles into the cement was captured.