Process for enhanced oil recovery using the asp technique

Abstract

The present invention relates to a process for the enhanced recovery of oil in a deposit owing to the introduction, into the deposit, of an alkaline aqueous solution of a water-soluble polymer containing a surfactant, characterized in that the aqueous solution of water-soluble polymer introduced is prepared with an aqueous solution initially containing Ca2+ and Mg2+ ions treated with an alkaline agent and a dispersant, so as, prior to the introduction of the polymer and of the surfactant into the aqueous solution, to precipitate, under the action of the alkaline agent and of the CO2 optionally dissolved in the aqueous solution, the Ca2+ and Mg2+ ions, especially in the form of precipitates of calcium carbonate and of magnesium hydroxide, and to disperse said precipitates owing to the dispersant, chosen in order to limit the size of the calcium carbonate and magnesium hydroxide precipitates formed.

Dependencies are inferred from the claim text.