The article provides an analysis of cement stone in conditions of steam injecting wells of high-viscosity oil and bitumen fields. The development of high-viscosity oil and bitumen field is one of the methods for maintain the required level of hydrocarbon production in conditions of falling production at traditional fields. Implementation of thermal enhanced oil recovery methods places additional demands on plugging materials properties, since traditional cements are non-effective at the temperatures above 100 °C because of strength loss of and increased permeability in the result of thermal corrosion processes. In high-temperature wells the initial hardening of the solution be gins at low temperatures (5-20 °C), this always leads to the formation of hardening products with a high ratio of CaO/SiO2. After heating agent injection these products begin to re-crystallize into thermodynamically more stable phases. At the same time, before more stable phases appearance, the initially formed curing products can go through several intermediate stages, inevitably worsening the physical and mechanical properties of the stone. Taking into account the conditions of hardening and operation of cement stone, it is proposed to combine Portland cement and silica-containing additives in the design of the composition of plugging material to ensure the required ratio of CaO/SiO2 in the binder, as well as to carry out its mechanization to increase the activity of the silica component. To minimize re-crystallization processes during the hardening of cement, it is proposed to take into account the kinetics of phase formation of hardening products. The requirements for the composition of plugging material and the properties of the resulting solutions to ensure the normal cementation process with good results are substantiated.
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