The Experimental Concentration Optimization of the Binary System of Oil Displacement in Offshore Oilfield

Abstract

In view of the formation characteristics as the high viscosity and the high permeability of offshore heavy oil reservoir, simulation of artificial core was developed. The indoor physical simulation experiments under the offshore oil field reservoir conditions were conducted. The effective viscosity of the binary system in the core was determined by the experiment. The corresponding capillary number was calculated according to the effective viscosity and experiments measured the relation curve between the capillary number and the oil displacement efficiency. When the capillary number gets higher, the system recovery efficiency is higher, and the residual oil saturation is lower. With the capillary number increasing, the increase scope of recovery and the decrease scope of residual oil saturation both increase gradually; The capillary number exists a critical value when the order of magnitude between 10-2~1 0-3. When the capillary number is greater than the critical value, it can improve the displacement efficiency greatly. When the capillary number is around 10-1, the oil displacement efficiency and the residual oil saturation tend to be stable. According to the capillary number and oil displacement efficiency curve, optimize the binary system in which the polymer concentration is 1750mg/l and the surface active agent concentration is 0.2%.