Since 1975, RWE-DEA has carried out numerous successful polymer field projects. In the reservoir units where injection had been initiated in the late seventies, production is close to being terminated- or can be estimated rather precisely by extrapolation of the concentration-versus-time profile. Polyacrylamide loss is calculated on the basis of injection and production data and amounts to 15 to 24 pg/g- or 25 to 53 μg/m2, respectively. Taking into account several correction factors, characteristically specific field retention values are in the range of 8 to 14 μg/g- or 13 to 28 μg/m2, respectively.
Field retention values are compared to polymer retention values determined in laboratory flood tests on packs of crushed reservoir core material and surface sands. As a general trend, polymer losses observed in laboratory tests are higher than those experienced in field applications. Possible interpretations are discussed.