Permeability contrast correction employing propionate-sequestered chromium(III) prepared by nitrite/dichromate redox

摘要

A process for preparing clear green chromium(III) propionate solutions which comprises admixing such as propionic acid with water, a chromium(VI) source such as dichromate, adding thereto a nitrite, such as sodium nitrite, to reduce the chromium(VI) to chromium(III), in the presence of excess acid, preferably propionic acid, optionally combined with additional acid such as muriatic acid, to produce a stable solution useful with polymers, such as partially hydrolyzed acrylamide-based polymers, in permeability contrast correction procedures for high permeability streaks in oil field treatments.