Experimental Study of the Permeability of Gravel Layer

In view of invasion problem of gravel layer by formation sand in actual production process,through the indoor simulation experiment,further study has been conducted on permeability variation of gravel layer after invasion by formation sand.The experimental results show that sand control result of gravel layer is closely related with matching degree between gravel and formation sand.The permeability of gravel layer is related with formation median grain size,nonuniformity coefficient,shale content and drawdown pressure,under the case of other influence factor unchanged,gravel layer permeability is proportional to formation median grain size;is inversely proportional to shale content,nonuniformity coefficient and drawdown pressure.The study provides a basis for forecasting the productivity with the change of gravel layer permeability,which has certain significance for guiding engineering practice.