Experimental Study On Microscopic Flow Visualization Of Micron And Nanoparticles

For macroscopic one-dimensional core flooding experiments,it is impossible to directly reflect the deficiencies of particle-liquid-solid multiphase mechanism and microscale flow characteristics in porous media.In order to improve these deficiencies,the two-dimensional visualization microscopic models are used to study the flow characteristics and oil displacement mechanism of micron and nanoparticles.Firstly,the static performance evaluation of micron and nanoparticles in microstructure research and particle size measurement are carried out through laboratory experiments.Secondly,the two-dimensional visualization micro-models are used to analyze the influence of different parameters on the oil displacement effect of the micron and nanoparticles system,and the microscopic mechanism of particles displacement.Finally,the one-dimensional core flooding experiments are used to further verify the correctness of the microscopic experimental results.Static experiments show that the microgel particles have an average particle size of115.21?m,uniform dispersion and good stability.The 2D smart nanocards have a size of about 100nm×80nm×1.2nm and exhibit neutral wetting characteristics.They are uniform and stable in the water phase,and have no obvious sedimentation at room temperature for 30 days.The experiments of oil displacement mechanism show that the microscopic oil displacement mechanism of microgel particles are mainly to increase the viscosity of the displacement phase,improve the mobility ratio,block the high permeability layer,enlarge the volume of the sweep and improve oil recovery.And the microscopic oil displacement mechanism of 2D smart nanocards mainly include wettability change,micro swirling flow and wedge penetration.The experimental results of two-dimensional visualization model show that the microgel particles system achieves the best oil displacement effect under the two-dimensional visualization model of permeability 2500×10^-3?m²,the particle concentration of 1.5wt%and the injection rate of 500?L/min.The 2D smart nanocards system achieves a better oil displacement effect in a two-dimensional visualization model with a permeability of 25×10^-3?m²,a particle concentration of 0.01wt%and an injection rate of 500?L/min.The synergistic effect of the two particles in the micro-nanoparticles composite system can effectively improve oil recovery.The oil displacement experiments show that the core flooding experiment is consistent with the corresponding two-dimensional visualization model experiment,which proves the correctness of the microscopic flooding experiment of the two-dimensional visualization model,and further verifies the correctness of the micro and nanoparticles flooding mechanism.