Modified particle retention model under effective stress influence due to reservoir depletion

The decline of reservoir permeability and consequent decrease in oil productivity are partly caused by particle attachment and detachment. A theoretical model of particle transportation is needed for petroleum production design and reservoir evaluation stage. A good understanding from the model calculation would also help to solve the formation damage problem and may contribute a better decision making to the petroleum developing project. A modified mathematical model for critical retention concentration of particle detachment is derived based on the mechanical equilibrium on the pore surface of the particle. The new model governs not only the impact of fluid velocity but also the impact of other reservoir physical properties as an influence of the effective stress. Due to the reservoir depletion circumstance, the oil production contributes to the pore pressure decrease and also the effective stress decrease, subsequently. The model simulation is also illustrated with sensitivity analysis of the model parameters, consistently resulting in monotonic decrease in that the higher the effective stress, the lower the critical retention concentration.