Abstract: The invention provides a membrane structure suitable for a sand production test of a rock sample provided with a hollow cylinder shape, the membrane structure comprising a main body with a housing configured to confine the rock sample within; a watertight outer wall adapted to withstand external hydrostatic pressure exerted by a first fluid; a permeable inner wall limiting the housing and configured to exert pressure on the rock sample and, to inject a second fluid into the outer surface of said rock sample; a plurality of internal hollow chambers located between the watertight outer wall and the permeable inner wall, wherein each one of the plurality of internal hollow chambers includes a plurality of rigid particles filling the inner space of each hollow chamber for transmitting the external pressure exerted from the outer wall to the inner wall.

Abstract: The invention provides a membrane structure suitable for a sand production test of a rock sample provided with a hollow cylinder shape, the membrane structure comprising a main body with a housing configured to confine the rock sample within; a watertight outer wall adapted to withstand external hydrostatic pressure exerted by a first fluid; a permeable inner wall limiting the housing and configured to exert pressure on the rock sample and, to inject a second fluid into the outer surface of said rock sample; a plurality of internal hollow chambers located between the watertight outer wall and the permeable inner wall, wherein each one of the plurality of internal hollow chambers includes a plurality of rigid particles filling the inner space of each hollow chamber for transmitting the external pressure exerted from the outer wall to the inner wall.