Method of treating a subterranean formation to remove ammonium ions

Abstract

An improved method of restoring a subterranean clay-containing formation having ammonium ions absorbed on the clay, wherein the formation is flushed with a halogenated restoration fluid having a halogen therein which reacts with the ammonium ion in the formation to decompose the ammonium ions is disclosed. The barren ammonia-containing restoration fluid, after it passes through the formation, is withdrawn, reconstituted and recycled as fresh restoration fluid back into the formation. The barren fluid is treated with an appropriate base to raise the pH to a highly alkaline level, the treated highly alkaline barren fluid is passed through an airstripping tower to strip substantially all the ammonia from the fluid, chlorine gas is added to the fluid from which the ammonia has been stripped, while controlling the amount of chlorine to produce a reconstituted restoration fluid of a predetermined pH level. Finally, the reconstituted restoration fluid is recycled back into the formation.

Dependencies are inferred from the claim text.