Transient ion exchange and solubilization of limestone in an oil field sandstone: Experimental and theoretical wavefront analysis



The competition between calcium-sodium ion exchange and the solubilization of calcium carbonate is studied in a column packed with a sandstone from an oil field. An equilibrium model accounting for this coupling is described. It is shown that the preflush used to eliminate the exchangeable calcium has only a transient efficiency and that the salinity of the water after the preflush can no longer be decreased to a very low level when the solubilization process occurs.