Transport of Nanogel through Porous Media and Its Resistance to Water Flow

Abstract

Abstract The application of nanoparticles in enhanced oil recovery (EOR) continues to gain attention in the oil industry due to its apparent potential. However, previous studies have focused on the evaluation of stiff particles, such as silica and aluminum oxide. In this paper, we present our experimental results of deformable nanoparticle transport behavior through porous media. Nanogel particles with sizes ranging from 100–285 nm were used to represent deformable nanoparticles. Core flooding tests were run using sandstone cores with water permeabilities ranging from 42 to 1,038 mD. We investigated the effects of the permeability, particle concentration, particle deformability, and flow rate on the particle propagation, resistance factor, and residual resistance factor (permeability reduction factor). The results show that the resistance factor ranged from 5 to 14 for rocks with permeabilities higher than 311 mD, indicating that the nanoparticles were able to transport easily through these rocks. However, the resistance increased to 383 when the permeability was as low as 41.2 mD, indicating that the nanogel could not penetrate the rock easily. After placing the particles, brine was injected at different flow rates. The results indicate that the nanoparticles effectively reduced the permeability of the rocks with the original permeabilities of 143 to 555.4 mD, but the residual resistance factor of the high-permeability rock (1,038 mD) was relatively small, ranging from 2.67 to 4.39. The resistance factor and residual resistance factor increased with the particle concentration and decreased with the flow rate, and both factors can be well fitted using power law equations as a function of velocity. The nanogel adsorption layer thickness decreased with the shear rate.