Scientific research and field applications of polymer flooding in heavy oil recovery

The heavy oil resources worldwide are estimated
at 3,396 billion barrels. With depletion of light oil,
we have to face the technical and economical challenges of
developing heavy oil fields. Due to severe viscous fingering,
the recoveries of heavy oil reservoirs are often below
20% or even 10%. Thermal methods have been successfully
applied in many heavy oil fields. However, reservoirs
at great depth or thin pay zones are not good candidates for
thermal methods.
According to past experiences, polymer flood was not
recommended for oil viscosity higher than 100 centipoises.
In recent years, polymer flood becomes a promising technology
for heavy oil recovery thanks to the widespread use
of horizontal wells. This paper highlights the research
advances of polymer in heavy oil recovery since 1977. In
laboratory tests, polymer achieved tertiary recovery of
more than 20% for heavy oil. A few field cases in China,
Canada, Turkey, Suriname and Oman are also reviewed
and analysed. Some field pilots have shown positive
results. Field experiences indicate the major challenge
facing polymer flooding effectiveness is to maintain good
viscosity of polymer solution.