用于热采井，在注热和采油交替过程中，更换管柱时不需要压井作业，避免压井液对地层造成污染 和冷伤害，降低开采效果问题。关键的配套工具是热采悬挂密封器、热采井下开关、插管密封器。

◎ 管柱在高温注汽和中低温起出时，均密封可靠

◎ 注汽管柱和生产管柱转换过程中不需要压井，能够避免压井带来的油层污染问题

◎ 热采悬挂密封器双重密封，可靠性高

◎ 插杆控制井下热采开关的开启和关闭，可反复开关，开关状态容易判断。

This string is used in thermal recovery wells. When the injection operation is changed to production or vice versa, it   is unnecessary to kill the well. So the pollution and cold formation damage caused by killing fluid can be avoided.   The key tools are hanging packer, underground switch and plug-in sealer.

◎ The sealing is reliable both for injection under high temperature and tripping in under low – medium temperature;

◎ Unnecessary to kill the well when changing the string, avoiding formation pollution;

◎ Double sealing;

◎ Pin lunge is used to change the switcher, easy to judge on or off situation.