In the dissertation work the regularities in formation of the rheological and physical and mechanical properties of the lightweight alkaline backfill mortar (LABM) of the system "ground granulated slag - complex of alkali metal compounds - complex of mineral additives - surfactants" for variables conditions of application (temperature 22-75 оС and pressure 0,1-35,0 MPa) for oil and gas wells with low, normal and temperate temperatures were identified. Technological methods for managing these properties were developed. The efficiency of regulation of rheological and physicomechanical properties of the LABM in variable conditions is shown by its modification by organic substances with the determined priority of the features of the molecular structure of aliphatic compounds, performing the role of surface-active reagents in such conditions. By the example of polyols and polyethers, it was concluded that the effectiveness of such admixtures increases in accordance with the increase of hydrophilic properties and molecular mass. And sorbitol, as surfactant with the largest molecular mass and the number of hydroxyl groups among alcohols, ensures compliance the flow of LABM to the Bingham's fluid in the variable conditions of well due to the manifestation of stable level of surface activity. The ways of regulation by rheological and physical and mechanical properties of the LABM are revealed due to application of synergistic effect of carbonates and sodium silicates in the alkaline component of alkali-activated slag cement (AASC) with aluminosilicate and calcium additives at low, normal and temperate temperatures in the well. It has been shown that depending on the temperature the content of the alkaline component must be limited to 5-10 % of slag in AASC, on the one hand, by decline of strength of cement stone and, on the other hand, by probability of the lack in activity of AASC. Adjustment of setting time and kinetics of hardening is ensured by the presence of Portland cement in LABM and sedimentation stability - by the presence of bentonite. It is shown that the dispersion of slag is additional factor for increasing strength of LABM with satisfactory rheological properties. Along with the reasonable choice of surfactants, complexes of alkali metal compounds and mineral additives, increasing dispersion of slag from 280 to 556 m2/kg, determines strength for bending tensile strength of LABM after 48 hours of hardening at t = 22 oC - up to 5 times, at t = 40 oC - up to 4.6 times, at t = 75 oC - up to 8 times. This phenomenon provides the required standardized strength of LABM. The technological parameters for production of LABM have been substantiated. It has been shown that by adjusting the angular speed of mixing in the range 1500-4125 rpm the contradiction between the positive influence of increasing the mixing speed on the decrease of density, water separation, increase of sedimentation stability and the negative influence on increase of the volume of involved air, water consumption, rheological properties is solved. In order to increase the efficiency of LABM due to separation from the drilling fluids, containing active substances in relation to slag in AASC as well as viscosifiers, the application of buffer liquids has been proposed.
