But there are inherent heat losses associated with long wellbore and heating surrounding rock formations that do not bear oil, so OSR is little and recovery efficiency is low.

• 但长井筒的热损失以及加热不含油岩层的热损失导致油汽比小 ,采收率低。克服热损失问题的一种潜在方法是用溶剂替代蒸汽。该方法称之为溶剂蒸气抽提法。