Preparation of a water control polymer treatment at high temperature and salinity conditions

The reservoir conditions in the northern Germany oilfield of Ploen-Ost on which RWE DEA is the operator are well-suited for the application of water control polymer technology in production wells. Polymers are expected to improve reservoir conformance around the wellbore and thus to stimulate oil production from the lowest permeability layers while reducing water influx from the highest permeability ones. The high temperature (95°C) and salinity (130 giL TDS) of the reservoir led us to test two new polymers, namely HST and Polysaccharide G, which have a better stability than polyacrylamides. Both polymers can selectively reduce the relative permeability to water of Ploen sandstone cores, with little effect on the relative permeability to oil and can thus be considered as valuablewatercontrol agents. Because of its higher shear resistance and its stronger shear-thinning behavior, Polysaccharide Gis expected to be easier to handle than HST.