Methods of treating a well bore within an underground formation are disclosed. These methods include: (a) preparing a treatment composition by mixing a polyol-containing component and a polyisocyanate-containing component; and (b) introducing the treatment composition into the well bore. The polyol-containing component includes a polymeric polyol having a viscosity at 25° C. of no more than 1000 mPa·s and the isocyanate-containing component includes an unblocked (cyclo)aliphatic polyisocyanate polymer including allophanate groups and having a viscosity at 25° C. and at least 99% solids of no more than 1000 mPa·s.