热采井中套管偏心对井筒温度场和应力场的影响研究

Effect Caused by Casing Eccentricity in Thermal Well on Wellbore Temperature Field and Stress Field

针对热采井中套管在圆形井眼中出现偏心的问题建立了有限元模型,分析套管偏心对井筒温度场和套管应力、位移的影响。套管偏心改变了井筒温度场沿井筒中心的分布方式,套管偏心程度越大,井筒温度场分布越不均匀。综合考虑了地应力、热应力以及注蒸汽过程中套压的共同作用,有利于精确地模拟热采井井筒的实际受力状况。结果表明,随着套管偏心率增大,套管上产生的等效应力值逐渐变小;套管偏心率的存在改变了套管内壁上等效应力分布的均匀性;套管在井眼中的偏心率越大,套管变形越大。

Aiming at the problem that eccentricity of casing in circular hole happened in thermal well, the finite element model is established and the effect of casing eccentricity on wellbore temperature field, casing stress and displacement were analyzed. The casing eccentricity has changed the temperature distribution along wellbore center, the larger the casing eccentricity of casing being the more non-uniform the temperature distribution becoming. Geostress, thermal stress and casing pressure are generally considered in the stress analysis in order to accurately simulate load stress of wellbore, which is beneficial to simulate the real wellbore condition of thermal well. The equivalent stress on casing decreases gradually with casing eccentricity increasing. The uniform of equivalent stress on casing is affected by casing eccentricity. The larger the casing eccentricity in hole is, the larger the casing deformation becomes.