Numerical simulation of sand production in oil well considering particle size effect

Considering particle size distribution curve of practical reservoir sandstone, a numerical model based on PFC3D under Cylindrical Coordinate System has been proposed to simulate sand production considering the fluid pressure gradient force and drag force based on similarity principle. Macro stress distribution indicated that introduction of fluid flow disturbed the mechanical condition of the reservoir sandstone, and larger flow rate increased the stress value more greatly; the mean stress and deviatoric stress reflected the development of the plastic zone when flow rate increasing, and this increased the probability of the sand yielding with the maximum plastic zone 16.5 mm, which indicated the localized effect. And the stress on parallel bonds indicated broken bonds near the inner hole, and when the flow rate was more than 2 m/s, stronger arch effect in radial direction could prevent the particles separating from the sandstone. The above results have showed the similar variation as the macro stress distribution, and also indicate that the forward numerical model considering particle size effect can reflect the practical mechanism of sand production.