Research on improving oil displacement efficiency using viscoelastic behavior of polymer

Key words:  viscoelasticity  the first normal stress difference  slope of the first normal stress difference  Wesson Borg number  oil displacement efficiency  residual oil saturation  field test

Abstract:

Some physical simulation experiments were conducted. The effects of the first normal stress difference N₁, the slope of the first normal stress difference SN₁ and Wesson Borg number on oil displacement efficiency and residual oil saturation based on slightly oleophilic artificial physical model were studied. Under the same viscosity conditions, the oil displacement efficiency was investigated. Two high concentration polymer flooding field tests were carried out in Daqing Oilfield. The results demonstrate that with the increase of the first normal stress difference, the slope of the first normal stress difference and Wesson Borg number, the oil displacement efficiency increases and residual oil saturation decreases. Under the same viscosity conditions, the oil displacement efficiency of polymer flooding was higher than that of the glycerol flooding significantly because of the elasticity of polymer. The oil recovery efficiency is greatly improved because of high viscoelastic behavior of high concentration polymer.