The Flow Characteristics of Fractured Viscous Fluids in Dense Conglomerates

The use of underground space to store oil is affected by fractures, which is simplified to a single-fracture seepage problem. Introducing the Reynolds number R_e and using 3D printing technology, physical model tests are conducted to explore the influence of the hydrodynamic viscosity μ and the fracture aperture b_i on the fluid flow characteristics and pressure gradient J under different injection flow rate gradients. The results show that: The fracture aperture b_i affects the stabilization time of the seepage, while the hydrodynamic viscosity μ has a greater impact on the seepage pressure. After fitting the data, it is found that the fracture aperture b_i has an exponential function relationship with the pressure gradient J, which shows a downward trend as b_i increases. At the same time, the Reynolds number R_e decreases, and the fluid flow capacity weakens; the hydrodynamic viscosity μ and the pressure gradient J show a downward trend. According to the relationship of the power function, J increases with the increase of μ, which reveals the evolution law of pressure gradient with hydrodynamic viscosity, indicating that the resistance of fluid flowing into the fracture increases and the inflow is more difficult. The fracture aperture and hydrodynamic viscosity have varying degrees of obstruction to fluid seepage in the fracture. Under the influence of multiple factors, the flow capacity is weakened, and blockage may occur. In a groundwater environment, oil can be stored at a certain height, indicating that it is possible to store petroleum-like viscous liquids in underground spaces containing tiny fractures without sealing measures.