中文摘要：

热力采油是开采稠油的最广泛、效益较高的方法．实践表明，注蒸汽稠油井如果用常规方法固井，那么在通常的注汽温度下，套管都因热应力而产生屈服变形．文中提出了防止热采井套管热破坏的预膨胀固井技术，即在注水泥结束但没有凝固时，将油层套管预热和向油层套管施加内压强，使套管膨胀；水泥在套管膨胀的条件下凝固．计算表明，采用预膨胀固井技术后，热采井在整个生产周期内，套管不但不屈服，而且还有较大的安全系数．室内实验证明，注汽后，采用预膨胀固井的套管的塑性变形量远小于常规固井的套管的塑性变形量．此项技术可能成为延长热采井套管使用寿命的重要手段．

英文摘要：

Thermal recovery is a very common and effective technique for heavy oil extraction. Failure of casing is often encountered in thermal recovery wells. In steam injection process, casing pipes are heated very seriously, which will result in plastic deformation when the thermal stress within the pipe exceeds the critercal point. In this paper, we present a pre-expansion technique to protect casing from thermal failure in thermal recovery wells, i. e. , the pipes for thermal recovery wells will be pre-expanded by heating and applying inner pressure before the cement solidifies. Calculations show that casing pipes with pre-expan- sion treatment will be without failure presence and possess greater safety coefficient during the whole pro- duction period. Laboratory experiments verify that plastic deformation of the casing pipes in steam injec- tion wells after pre-expension treatment is much smaller than that in coventional cementing wells. This technique can prolong the service life of thermal recovery wells largely.