NOVELTY - The method involves introducing treatment fluid e.g. spacer fluid, into a subterranean formation, where the treatment fluid comprises a metal oxide. A chelate complex or coordination complex is allowed or caused to form between the metal oxide and a ligand. The chelate complex or coordination complex is allowed or caused to set. A complex network is formed by cross-linking the chelate and coordination complexes. A cross-linking agent is introduced into a well, where the agent comes in contact with the chelate and coordination complexes, and cross-linking agent forms the complex network.    USE - Method for treating vertical, inclined and horizontal positions i.e. open or cased hole wellbore portion, of a subterranean formation in a well e.g. oil, gas or water production well, injection well and geothermal well.    ADVANTAGE - The method enables setting chelate or coordination complex to bind lost-circulation material (LCM) particles together, thus improving efficiency of the LCM and reducing mount of liquid lost into the subterranean formation, and hence providing improved substances that have lower thermal conductivity to be used in a treatment fluid, allowing substances to coat wellbore parts in an effective manner and enhancing fluid additives to exhibit improved properties and optionally meet environmental regulations. The method enables allowing a filtercake to bind fines i.e. sand, to reduce damage to formation permeability and stabilize the wellbore.    DETAILED DESCRIPTION - The metal oxide is selected from a group consisting of oxide or hydroxide of zinc, aluminum, calcium, tin, barium and magnesium. The chelate complex or coordination complex is selected from a group consisting of a lost-circulation material, a binder for a lost-circulation material, a zonal isolation material, a binder for drill cuttings, a thermal insulator, a binder for a thermal insulator, a binder for proppant or gravel, a frac plug, a fluid-loss control material, a binder for a fluid-loss control material and a sacrificial wear material. The ligand is polydentate and eugenol, and comprises a functional group selected from a group consisting of a carboxylate, an amine, an alcohol, an ether, a phosphate, a thiol, a thiol ether, isocyanate, isothiocyanate and cyclopentadienide.