Vacuum-insulated steam-injection system for oil wells

摘要: In an apparatus for delivering a heated fluid to subterranean productive formation, injection system is provided in which outer, insulating tubing surrounds the tubing, preferably throughout substantially its entire length. At least partial vacuum maintained space between and tubings provide heat barrier, minimizing losses from tubing. With this construction, can be held but small percentage of uninsulated (6 claims)