Method for treating subterranean, clay-containing earth formations

Abstract

Disclosed is a method for treating subterranean earth formations containing appreciable amounts of water-sensitive clays, including petroleum-containing formations, in order to render the clay content of the formation less sensitive to swelling and other phenomena which cause reductions in permeability of the earth formation when the clay content is contacted with relatively fresh water. The method involves contacting the clay with an aqueous solution of a chelated polyvalent metal ion, specifically chelated transition metal ions, including magnesium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, silver, cadmium, iridium, platinum, gold, mercury and lead. The chelating organic ligands are ethylene diamine, diaminopropane, diaminobutane, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, tris(aminoethyl)amine, triaminopropane, diaminoaminoethylpropane, diaminomethylpropane, diaminodimethylbutane, bipyridine, dipyridylamine, phenanthroline, aminoethylpyridine, terpyridine, biguanide and pyridinealdazine.

Dependencies are inferred from the claim text.