固井界面接触热阻对井筒温度场预测的影响

Influence of Thermal Contact Resistance of Cementing Interface on Prediction of Wellbore Temperature Field

固体界面不完整接触会产生接触热阻。为研究固井界面不完整接触产生的微环隙对井筒温度场预测的影响,推导了接触热阻计算方法,并设计空气条件下测试接触热阻的实验进行了验证,最后研究了不考虑固井界面接触热阻的经典方法在预测井筒温度场时产生的偏差。结果表明:接触热阻与接触表面的间距和温度有相关性;固井界面微环隙增大(0.05~1 mm)、注蒸汽时间增加(2~40 d)、地层温度升高(305~400 K)等情况下,预测井筒温度场时不考虑固井界面充填气体的微环隙,将使计算的水泥环外壁温度略有偏低(约3 K),而水泥环内壁温度和地层内壁温度偏高较大(约14 K)。提出的将固井界面接触热阻应用到井筒径向传热的方法,可以使井筒温度预测更符合现场实际。

Incomplete contact at solid interface will produce thermal contact resistance.In order to study the influence of micro-annulus caused by incomplete contact of cementing interface on prediction of wellbore temperature field,the calculation method of thermal contact resistance was deduced and verified by experiment.Finally,the deviation of classical method without considering thermal contact resistance of cementing interface in prediction of wellbore temperature field was studied.The results show that the thermal contact resistance is related to the spacing and temperature of surfaces.If not considering the interfacial thermal contact resistance t when predicting the wellbore temperature field,when the width of micro-annulus increases(0.05~1 mm),the time of steam injection increases(2~40 d),the temperature of formation increases(305~400 K),the calculated outer wall temperature of the cement sheath will be relatively low(about 3 K),while the inner wall temperature of the cement sheath and formation will be relatively high(about 14 K).The proposed method of applying thermal contact resistance of cementing interface to wellbore radial heat transfer can make wellbore temperature prediction more suitable for the actual situation.