Methods using an anchoring agent for a water-soluble polymer that is in-place polymerized in a subterranean formation. The anchoring agent comprises a hydrolyzable silyl group that reacts with one or more dangling hydroxyl groups of a mineral surface in the subterranean formation to form “hard” bonds, “anchoring” to the mineral surface. The anchoring agent is selected to have another functional group for covalent attachment to the water-soluble polymer. This can help a water-soluble polymer be anchored to a mineral surface in a subterranean formation. Accordingly, it is believed that monomolecular layers of water-soluble polymer will be formed and anchored to the mineral surface, which will provide excellent elastic properties to the matrix. The monomolecular layers are not expected to interfere with the permeability of the matrix.