Abstract:

It is well known that the supercritical CO₂ has the dual characteristic of gas and liquid. In order to study the forces of the sand in the fluidized bed formed by the supercritical CO₂ fracturing fluid and the migration of the proppant particle under the force, we analyzed the acting force between two particles, and the particle and the fluid, and that of the fluid on the particle. Based on the mathematical model, we derived the relation between the elastic restitution coefficient and the agglomeration concentration of particles. With the increasing of the elastic restitution coefficient, the distribution of the agglomeration concentration gets more evenly, the agglomeration concentration decreases, the collision of particles is more intense, the particles settle down more slowly, and the sand migration effect is better. Meanwhile, through the numerical simulation of the double Euler multiphase model based on the particle kinetic theory, we described the fluidization model in the fluidized bed formed by the supercritical CO₂ fracturing fluid in operation, and the two phase distribution of the particle of the supercritical phase and the solid phase. The simulation result is consistent with the mathematical model.

Key words: proppant, agglomeration of particle, elastic restitution coefficient, double Euler model, granular settlement