Most oilfields have entered the later development stage, and the pore pressure is seriously depleted. Pressure depletion influences the in-situ stress of the reservoirs and changes the stress state around the boreholes, as well as affects rock strength by causing the compaction of the formation and reducing the porosity of the formation. These two factors synergistically exert influences on the critical drawdown pressure of sand production. Based on the generalized Hoek's law, the theoretical formula representing the change of two horizontal stresses with pore pressure is obtained. The formula was used to analyze the stress distribution around the boreholes in pressure depleted reservoirs. Moreover, exploring the relationship of pore pressure depletion with variation of rock strength and in-situ stress, the model for calculating the critical bottom hole flowing pressure in pressure depleted reservoirs was constructed. The formula was used to analyze the influence of pressure depletion on the critical drawdown pressure of sand production. The results showed that pressure depletion reduces the critical drawdown pressure of sand production, and the reduction level is less than that of pore pressure; while the strength increase resulted from pressure depletion increases the critical drawdown pressure of sand production and reduces the probability of sand production. The establishment of the prediction model provides the guidance for actual production decisions in pressure depleted reservoirs.

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