Composite Binders for Fastening High Temperature Wells

Abstract

The article deals with the hydration of oil-well cement, intended for cementing high-temperature wells. At high temperatures and pressures (150°C, P = 30 MPa) Portland cement stone does not have the necessary density and resistance to high temperatures due to the formation of hydrated calcium silicates rich in lime during the hydration of Portland cement, therefore, the work was carried out primarily to find appropriate additives to Portland cement, providing the necessary properties of oil-well cement. From a number of additives to ensure the durability of service were selected reprocessing waste of titanium ores (titanomagnetite concentrate) and blast furnace slag. In addition, to improve the crack resistance of cement stone, the possibility of using expansive additives to oil-well cement was investigated. For these purposes, sulfoaluminate, sulfoferrite clinkers and alumina slag were used.It has been established that during hydration of calcium sulfoferrite ferrous ettringite is formed, which is more stable at elevated temperatures than ettringite formed at hydration of sulfoaluminate clinker and alumina slag. In the presence of sulfated phases and silica, at elevated temperatures and pressures, low-base calcium silicates hydrates and iron contained garnet hydrates are formed.