The regularities of changes in physical and mechanical properties of polymer-cement composition with low content of dispersion medium have been investigated. It has been proved that the introduction of high-molecular polymer "Konkripol" into polymer-cement mortar composition allows to increase compressive and bending strength of cement stone, its adhesion to metal while maintaining the required mobility of the mixture. This contributes to improving the quality of interlayer isolation of the casing space in oil and gas wells.