The primary recovery of some heavy-oil reservoirs can reach relatively high values by using solution-gas-drive technology in which gas dissolved in heavy oil is released and drives the oil when the formation pressure drops below the bubble point. Rheological properties of foamy oil in porous media were studied using conditions of the Orinoco heavy-oil belt in Venezuela as examples. The relative mobilities of foamy and normal oil were compared in core flooding experiments. Improvement of the oil phase as a result of forming the foam structure was analyzed. The research results could be useful for understanding the mobility parameters of heavy oil and increasing the recovery efficiency in heavy-oil reservoirs.