to decrease the quantity of polymer required per barrel of oil produced which constitutes a spectacular breakthrough compared with existing processes the invention will now be illustrated more completely with the help of non limiting examples and in particular which cannot be considered as limiting for the compositions and forms of the polymers pressure 100 bar temperature 45 u00b0 c salinity 5000 ppm tds oil viscosity 25 cps water viscosity 0 6 cps vertical horizontal permeability kv kh 01 s wir u201c irreducible water saturation u201d proportion of water present in the well 0 25 s or u201c residual oil saturation u201d proportion of non recoverable oil in the well 0 30 injection rate 200 m 3 h the downhole pressure is maintained below the fracturing pressure of 170 bar start of production 80 m 3 day per well this start can be adjusted to maintain the minimum downhole pressure of the producing well at 10 bar the polymer injected is an acrylamide sodium acrylate copolymer having a molecular weight of 15 million it is dissolved in stock solution by the use of a psu wo 2008 107492 under nitrogen containing less than 200 ppm oxygen at a concentration of 10 g litre with an initial oxygen.