Pore seepage law based on 3D printed micro-pore model

The study of porous media seepage law is the basis for oil,gas and water resources exploitation and water disaster prevention while a physical model test is an important means to carry out the research on it. Based on the CT image of real sand sample,through the steps of shearing→binarization→boundary extraction→modeling,a two-dimensional pore model was constructed. Using a high-precision light-solid 3D printer and rigid photosensitive material,a transparent fine pore test model was constructed. With a test platform including water injection system,pressure monitoring system,observation system,pore test model and pipeline,12 injection water flow gradients and 4 seepage directions were tested for seepage model,which realized the observation of pore seepage process and high-density real-time monitoring of water injection pressure. The study found that ① in the process of porous media seepage,diversion and confluence continue to occur. The experiment model has a large difference in the active degree of pore seepage at different positions;② the relationship between hydraulic gradient and permeability coefficient is a power function,and the larger the hydraulic gradient,the stronger the correlation;③ the relationship between seepage velocity and hydraulic gradient is a highly correlated quadratic function. When the plane changes the injection direction at 90°,the hydraulic gradient varies greatly,showing obvious anisotropic characteristics;and ④ the porous model is a mixed flow of “laminar flow+turbulent flow”,with the increase of seepage velocity,the proportion of turbulent flow in hydraulic gradient increases,which is mainly related to the characteristics of pore structure.