Patent ID: 7458424

Claim:
A method of inhibiting permeability of a portion of a subterranean formation, comprising: preparing a stable aqueous colloidal dispersion comprising from about 15 to about 70 weight percent of silica particles having an average particle size from 4 to 300 nm and a surface modification with negative ions, from 0.1 to 5 weight percent of a thermally activatable hydroxyl donor, and having a pH of from about 9 to about 12; injecting the colloidal dispersion into a portion of a subterranean formation having a temperature above the thermal activation temperature of the hydroxyl donor to elevate the pH; setting the colloidal dispersion into a hard gel in place for from 1 to 12 hours in the formation to inhibit water permeability of the portion of the formation; and producing a fluid selected from oil, gas and water from a remaining portion of the formation.