US Patent 7798222 Expandable fluid cement sand control

A system for preventing the migration of unconsolidated and/or loosely consolidated material into a wellbore. Such prevention is accomplished by introducing a well treatment medium comprising an expandable fluid and a bonding agent into an unconsolidated zone proximate the wellbore. The expandable fluid is allowed to expand and flow through the unconsolidated zone while the bonding agent cures, thereby forming a consolidated zone having sufficient porosity to allow fluid flow therethrough.