New silicate hydrogel with more elasticity as in-situ water diversion system: preparation and investigation of rheological and pugging behaviours

Abstract

Silicate-based gels are used in water diversion treatments for its low cost and environmental safety. In this paper, a new hydrogel with an interpenetrating network is developed based on three components, sodium silicate (Na2O.mSi2O), hydrolysed polyacrylamide (HPAM) and an activator. The interpenetrating network of Na2O.mSi2O-HPAM-activator is proposed. In the presence of an activator, Na2O.mSi2Oformsa brittle sodium silicate gel, while Na2O.mSi2O and HPAM forms an elastic gel resembling a polyacrylamide gel. In the Na2O.mSi2O-HPAM-activator system, the sodium silicate hydrogel may be weakly bound by hydrostatic forces to the polyacrylamide molecules. Polyacrylamide tends to wrap around the silicate hydrogel due to these hydrostatic forces, and produces an inorganic-organic interpenetrating network. The gelation time and the gel strength of this new silicate hydrogel system depend on the component concentrations. Furthermore, the rheological and plugging behaviours of this system with inorganic-organic interpenetrating network are investigated. The new three-component hydrogel features at unable gelation time, stronger gel strength, viscoelasticity, low cost and low environmental impact, which can be widely applied as in-depth water diverting agent in injection profile control.