Wells are typically drilled for exploration and production of oil, gas, water or geothermal energy from the underground.

Well cements are needed for providing an effective zonal isolation (hydraulic seal) and anchoring of steal pipes (casings) in such wells. The cement sheath between the formation wall and the casing string shall ensure proper flow of production fluids into the well. Leaky cement sheaths may lead to loss of production fluids from the payzone into other formations or even to dangerous blowouts to the surface. Defectively conducted cementing jobs are not easy to repair and in many cases not at all. Providing an effective sealing is made more difficult by extreme temperature and pressure conditions especially in wells for production of oil and gas from deep formations or in geothermal wells (up to 350 C).