POLYMER FLOODING IN ENHANCED OIL RECOVERY (EOR)
Ayshan KHALAFLİ
Qafqaz university
axelefli-1@std.qu.edu.az
The significance of oil in the world economy cannot be overstated, and methods for recovering oil will be the subject of
much scientific and engineering research for many years to come. Even after the application of primary depletion and
secondary recovery processes (usually water flooding), much oil usually remains in a reservoir. Thus, there is an enormous
incentive for the development of enhanced methods of oil recovery, aimed at recovering some portion of this remaining oil.
One of the most effective chemical methods in EOR is polymer flooding.
Polymer flooding has proved economically and technically successful in numerous EOR projects, which has shown
some successes to recover more than 20% of the original oil in place (OOIP).This method improves the vertical and real
sweep efficiency as a consequence of improving the water/oil mobility ratio. In addition, the polymer reduces the contrasts
in permeability by preferentially plugging the high permeability zones flooded by polymers. This forces the water to flood
the lower permeability zones and increases the sweep efficiency.
In the polymer flooding technology, surfactant polymer is injected to the reservoir to reduce an interfacial tension
between oil and water and is able to wipe out the trapped oil from the reservoir rock and hence increase the oil production.
While an injection of hydrogel polymer to the reservoir is to increase a viscosity of fluid containing water so that the fluid is
more difficult to flow than the oil, and as a result, the oil production increases. The most common polymer used for this
application is polyacrylamide group.
However, there are limitations with the existing polymer technology such as degradation (thermal, physical, bacterial,
and chemical) or polymer rheological. HPAM as the most common used polymer recently also suffers from strict temperature
and salinity limitations. It is important to select the proper polymer for a particular field. Reservoir permeability and oil
viscosity are used to determine the optimum molecular weight polymer. Rock composition and polymer adsorption level are
used to determine the best degree of hydrolysis.
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