Gelation of chromium(III)/xanthan systems in dolomite core material for in-depth matrix rock treatments was investigated. The gels contained approximately 2,000 ppm xanthan and the dolomite core material was obtained from a San Andres dolomite reservoir in Texas and had permeabilities ranging from 4 to 10 md. Compositional changes in the gelant caused by interactions with the dolomite core material resulted in small permeability reductions for gelants prepared with chromium chloride, chromium acetate and a chromium diamine salt. The primary cause of incomplete gelation in the dolomite material was attributed to the increase in gelant pH that resulted in precipitation of chromium.
Keywords:ph value, viscosity, brine, dolomite matrix, permeability, rock/fluid interaction, gelation, chromium concentration, injection, precipitation
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