Particle migration behavior of fractured lost circulation control: Numerical simulation

Fracture loss is the most common type of leakage in petroleum drilling engineering. The existing numerical simulation of the particle transport process is relatively simplified. In order to clarify the dynamic behavior characteristics of bridging particles in fractures, this paper adopts the discrete element and computational fluid dynamics coupling numerical simulation methods to establish a bidirectional coupling numerical model of bridging particles and drilling fluid to simulate the dynamic evolution process of bridging plugging particles, such as migration, bridging, and accumulation. The results show that the main factors affecting the transport pattern of plugging particles in the fracture are differential pressure, particle size, drilling fluid viscosity, drilling fluid density, fracture width, and fracture length. The drilling fluid density has a small effect on the inter-particle force in the fracture; the drilling fluid viscosity mainly affects the resistance of the particles, and the pressure difference between the inlet and outlet of the fracture mainly affects the transport speed of the particles. The particle size determines whether a plugging layer can be formed, and the best plugging effect is achieved when the particle size is 1/2 of the fracture width.