This paper discusses the results of laboratory studies conducted to determine the potential for formation damage from alkaline condensates during steam injection in a reservoir in the San Joaquin Valley, California. The paper also reviews various remedial treatment options and recommends some optimal treatment injection sequences to sustain steam injectivity.
Laboratory flow tests conducted in field core plugs with condensates at different steam qualities reveal the tendency of the condensates to dissolve the rock, destabilize the clays, and hence reduce the permeability. The alkaline condensates from once-through steam generators were also found to be incompatible with the formation water, and thus had the potential to form calcium carbonate precipitates and scales.
Pretreament of boiler feeds and/or concurrent treatment of boiler effluents with either a low concentration (<0 .1 % wt.%) phosphoric acid in 2 % potassium/ammonium chloride solution or 2 % ammonium dihydrogen phosphate reduced silica dissolution, stabilized the clays and rendered the condensates more compatible with the formation water.