The main purpose of adding polymer to the injected water is to decrease the mobility of the flood water by increasing its viscosity to improve the oil displacement efficiency.
Therefore, increasing the flood water viscosity mitigates the viscosity contrast between oil and water and thereby improves the oil sweep efficiency [3-5], Furthermore, the microscopic displacement efficiency, which refers to the effectiveness of the injected water in displacing and mobilizing residual oil trapped at the pore scale by capillary forces, can be also improved during polymer flooding due to the elasticity of the polymer systems [35, 36], Therefore, the enhanced elasticity and viscosity of the optimum SAP system are both beneficial for increasing the overall oil recovery efficiency.
With this lower displacement efficiency
, the carbon gap is more significant, and it takes 23 years for the sustainable rate of carbon displacement to surpass the short-lived decay of forest residuals.
This mechanism may considerably improve water displacement efficiency
, and ultimately lead to higher oil recovery
In addition, it is indicated that polymer solution can improve microscopic displacement efficiency because of excellent viscoelasticity [XIA,2001; HUANG, 1990;].
Viscous-elastic polymer can increase micro-scale displacement efficiency in cores [J].
High biomass growth rates from short rotation woody crops offset much of the relatively low carbon displacement efficiency from producing ethanol.
0 tC/ha/y, as a consequence of the low carbon displacement efficiency in producing ethanol.
At this time, using polymer flooding can improve both Volumetric Sweep Efficiency and Oil Displacement Efficiency .
Compared with inelastic driving fluid, the deformation of polymer flooding is more obvious, the amplitude is larger and the oil displacement efficiency is better.
Apparently, an early breakthrough of bottom-water leads to a very poor water displacement efficiency.
The increased water displacement efficiency depends on the size of the low permeability zone.