Numerical investigation of sand production mechanisms in weak sandstone formations with various reservoir fluids

A three-dimensional CFD-DEM simulation method was developed to investigate the influence of different reservoir fluids on sand production. The fluid properties and reservoirs were prescribed and modelled after the conditions in the Kenkiyak and Uzen oil fields in Kazakhstan. A cylindrical sandstone sample was modelled using the Discrete Element Method in three stages of the pluviation, diagenesis, and perforation processes as in the oil field. A coupled simulation with the Computational Fluid Dynamics was used to simulate the sand production from the perforated sandstone under different fluid flow conditions with light and heavy oils. A continuous sand production was found to be more severe with the heavy oil flow due to its higher transport capability and a microstructural sanding mechanism that mobilized a higher proportion of the sample's particles with the fluid outflow. Sand production for light oil occurred in two stages of a first transient sand production that was followed by a second continuous sand production. The transient sand production was associated with more significant bond breakage, particle movement and porosity change within the damage zone that was created by the central perforation inside the sandstone sample.