STABILIZING POLYSACCHARIDE SOLUTIONS FOR TERTIARY OIL RECOVERY AT ELEVATED TEMPERATURE WITH DITHIONITE

摘要

A method of tertiary oil recovery from petroleum-containing formations at elevated temperature comprises injecting a substantially oxygen-free aqueous saline solution of water-soluble polysaccharide biopolymer treated at pH of at least 5 by the addition of alkali metal hydrosulfite (dithionite) as sole viscosity stabilizer which improves the high-temperature stability of the biopolymer in an economical and effective manner.