Effective Propagation of HPAM Solutions Through the Tambaredjo Reservoir During a Polymer Flood

Abstract

Abstract Two new methods were developed for anaerobically sampling polymer solutions from production wells in the Sarah Maria polymer flood pilot project in Suriname. Whereas previous methods indicated severe polymer degradation, the improved methods revealed that the polymer propagated intact over 300 ft through the Tambaredjo formation. This finding substantially reduces concerns about HPAM stability and propagation through low- and moderate-temperature reservoirs. Analysis of produced salinity, polymer concentration, and viscosity indicated that the polymer banks retained low salinity and therefore high viscosity for much of the way through the Sarah Maria polymer flood pilot pattern. A strong shear- thickening rheology was observed for 1000-ppm and 1350-ppm HPAM solutions in porous media, even though the salinity was only 500 ppm TDS. Examination of injectivities revealed that these solutions were injected above the formation parting pressure in the Sarah Maria polymer injection wells. Analysis suggested that the fractures extended only a short distance (~20 ft) from the injection wells and did not jeopardize sweep efficiency. In contrast, the short fractures greatly improved polymer injectivity and reduced concern about polymer mechanical degradation.