An Experimental Study on Permeability of Unsaturated Petroleum Chalk

Abstract:

The oil permeability and its influence factors in unsaturated petroleum chalk were studied by carrying out some experiments with a specially improved constanthead permeameter where the matrix suction was controlled with axistranslation technique.The results show that the permeability is closely related with the confined stress, hydraulic pressure and matrix suction. With the developing of confined stress,the chalk presents an evident pressuresensitive effect that both the void ratio and oil permeability decreas. The oil permeability drops down with the increasing of hydraulic pressure, so that the waterflooding in oil reservoir raises the water content in chalk, which will make the matrix suction and oil permeability decrease consequently. The results provide a reference for increasing the oil recovery in petroleum production.

Key words:reservoir rock; chalk; unsaturation; permeability