The Displacement of Oil from Porous Media by Micellar Solutions

Abstract

Abstract The increasing need for oil in today's world has focused attention on increasing the efficiency of displacing oil from reservoir rock. Recently the oil industry has become interested in oil recovery using miscible fluids. The purpose of this investigation was to study the effectiveness of micellar solutions in recovery of oil from porous media. The models used were linear sandstone cores, a linear model packed with various sands and a five-spot model packed with various sands and a five-spot model packed with sand. Models saturated with water packed with sand. Models saturated with water and different viscosity crude oil were subjected to micellar solution injection. Experiments were performed for both secondary and tertiary recovery performed for both secondary and tertiary recovery conditions. One hundred percent oil displacement by micellar solution injection was observed for all but one system. This exception occurred when a small slug of micellar solution was injected into a sandstone core and displaced with a Dow pusher. A small amount of oil was observed at pusher. A small amount of oil was observed at the outflow end of the core when small samples were cut from the core and examined. The laboratory experiments indicated that micellar solutions are an effective means of oil displacement. These solutions are effective because of their miscibility with the oil, controllable mobility, their stability in the presence of reservoir crude oil, water and rock, presence of reservoir crude oil, water and rock, and finally their incomplete removal of contacted water. Introduction Complete recovery of crude oil from an oil-bearing formation is not possible if the crude oil is displaced by an immiscible fluid such as water. Capillary forces retain part of the oil in the pores even though many pore volumes of the immiscible displacing fluid are passed through the system. To recover the oil trapped in the pores, the capillary forces must be zero. There are no capillary forces if the displacing fluid is miscible with the crude oil. For the past decade the oil industry has been interested in displacing oil from reservoir rock using miscible fluids. The miscible process has been used in fields when technically process has been used in fields when technically and economically feasible. A few years ago a micellar solution was developed that was miscible with oil and water. In 1967, this solution was described by Marathon Oil Co. To displace oil from reservoir rock, a micellar solution and then water were injected into a formation. The method was reported to result in a 100 percent displacement of oil. Micellar solutions used in this process consisted basically of three components: hydrocarbon, surfactant and water. In addition, a small amount of electrolyte and cosurfactants (e.g., alcohol) were sometimes used.