Experimental Study and Pore Network Modeling of Formation Damage Induced by Fines Migration in Unconsolidated Sandstone Reservoirs

Fine migration is always considered as one of the major mechanisms that are responsible for formation damage. The unwanted reduction of reservoir permeability would result in the decline of water injection and consequent oil production, especially for the unconsolidated sandstone reservoir. For better understanding, the mechanisms of formation damage in pore-scale, a new three-dimensional pore-scale network model (PNM) is proposed and developed to simulate formation damage caused by particle detachment, migration, and capture in pore throats based on force analysis. Experiments are also conducted on the formation damage characteristics of an unconsolidated core. Both X-ray diffraction and scanning electron microscope (SEM) are applied to understand the microscopic reservoir properties. The experimental results show that the studied core has a strong flowrate sensitivity. A comparison between experimental results and PNM simulation results is conducted. The simulated results agree well with the experimental data, which approves the efficiency and accuracy of the PNM. Sensitivity analysis results show that larger particle sizes, higher flowrate, higher fluid viscosity, and lower ion concentration of the fluids would contribute to the formation damage, which could provide guidance for the development of unconsolidated sandstone reservoirs with strong sensitivity.