Challenges of Cementing Steam Injection Wells SAGD

There are a number of high-viscosity oil fields around the world. A distinctive feature of such oil fields is a combination of two factors: high viscosity of oil and low temperature of its enclosing zone. Sometimes, the temperature of pay zone is comparable to the temperature of permafrost + 6 °C. Thermal methods are used to intensify oil production in such oil fields. The main thermal method is the injection of steam into the formation. The temperature of the injected steam exceeds 200 ° C. With using this technique of intensification, there is a challenge of keeping the integrity of the cement sheath behind the column, as the cementing conditions and operating conditions are incompatible. The curing of the cement stone occurs at a temperature about + 6 ° C. When the steam is injected, the cement sheath is heated to a temperature of + 195 ° C or more. Thermal deformations of the columns occur: expansion, elongation, when high temperature is applied. To reduce the probability of steam breakdown due to thermal deformations of the column, thermo compensators are used. Moreover, to compensate for the thermal elongation, the shoe of filter pipe is set upper than bottom was drilled.