A primary concern of the Petroleum Engineer is protection of wellbore casing and cement.  In a steam injection wells heat flux occurs across the entire length of injection tubing into the wellbore annulus, casing, cement and formation.  Steam injection wells completed with bare(non-insulated) tubing strings offer minimum resistance to this heat flux and both casing and cement will have elevated temperatures being nearly the same as the temperature of injected steam. This temperature effect causes thermal elongation and thermal stress on the casing directly proportional to the increase in casing temperature.  The use of Insulated Steam Injection Tubing (commonly called VIT – Vacuum Insulated Tubing) in one possible solution to mitigate these potential problems.