This paper reports some results of on-going research efforts to develop a method to reduce undesired gas production in oil wells by using foam as a barrier. Exploitation of the gas-blocking properties of foam by using it as a gas-coning barrier is an old idea that, to our knowledge, still has not been applied successfully. An attractive means of achieving a favorable barrier geometry is by using low-density non-aqueous foaming-agent solutions. This work is, to our knowledge, the first study of non-aqueous foams as gasblocking agents. We are focusing on two alcohols using fluorinated well-stimulation surfactant formulations. The ability of foam to reduce gas mobility in porous media was measured by a gas-blockage test. Most experiments reported are for a model system, but some data at higher temperature and in the presence of crude oil and brine are included. Experiments in porous media show that non-aqueous foams are capable of producing the same drastic changes in flow patterns as aqueous gas-blocking foams. Gas blockage is shown to be possible over an extended period, or at high pressure gradients, with a non-aqueous foam. The effects on gas blockage of varying the absolute permeability, porous-medium length, and temperature are also reported.

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