INFLUENCE OF INTERFACIAL REACTION AND MOBILITY RATIO ON THE DISPLACEMENT OF OIL IN A HELE-SHAW CELL

A comparative experimental study was conducted to examine the effect of fluid-fluid interfacial reaction on immiscible displacements in a wide range of mobility ratios. The nonreactive fluid pair consisted of paraffin oil/decane mixtures and water. In order to formulate a reactive system, linoleic acid (10 mol/m(3)) was added to the oil and sodium hydroxide (25 mol/m(3)) was added to the water. The experiments were performed in a square Hele-Shaw cell, simulating a quarter of a reversed five-spot pattern. Displacement patterns produced by reactive and nonreactive fluid pair systems were fundamentally different from each other. The recovery in the reactive system was generally higher than in the non-reactive system. The recovery at breakthrough for both the reactive and the non-reactive systems increased with a decrease in the viscosity of oil. In the non-reactive system, the recovery at one hour after breakthrough increased with the decrease in oil viscosity and became constant at 63% when the oil viscosity reached 6.86 mPa.s. In the reactive system the recovery at one hour after breakthrough was nearly 100% regardless of oil phase viscosity. When the oil viscosity was lower than the viscosity of the displacing phase (favorable mobility ratio), the recovery percentage was high. However, the jagged character of the displacement front characteristic of the reactive system was still preserved.