The potential for using lignosulfonate as a sacrificial agent to reduce adsorption of the primary foaming agent in CO2 flooding was evaluated in laboratory experiments. Circulation and flow-through methods were used to measure adsorption to assess the loss of surfactants for economic evaluation and to design an optimum surfactant injection scheme.
Results show that lignosulfonate could reduce the adsorption of a primary foaming agent by 24-60% in Berea sandstone and 15-29% in Indiana limestone core samples. The selective adsorption behavior of lignosulfonate and surfactant gives rise to various adsorption results with different injection schemes. Preflushing the core with lignosulfonate proved to be more effective in reducing the loss of primary foaming agent than coinjecting both foaming agents together. Considering the cost savings as well as the effectiveness of foams in improving oil recovery, an effective surfactant injection design with lignosulfonate shows significant potential for economically improving the CO2-foam flooding process.