注汽井井筒温度分布的模拟计算

SIMULATION MODEL FOR TEMPERATURE DISTRIBUTION IN STEAM INJECTION WELL BORE

现场使用的注汽井井筒模拟软件存在的主要问题是对隔热井筒的节点划分过粗 ,未考虑隔热油管接箍和伸缩管等对井筒温度分布的影响 ,其计算结果误差较大。针对这一问题建立了井筒温度分布精细描述数学模型 ,编制了新的计算软件 ,此软件考虑了接箍处轴向导热的影响 ,改进了地层热阻的计算方法 ,并采用新方法计算环空隔热介质的导热系数。对隔热油管外管壁温度分布进行的局部加密处理后的计算结果更能接近实际热损失情况。分别用数值解法和解析法求解了隔热管外管壁的温度分布。与现场测试数据的对比说明 ,精细模型计算的结果准确度高 ,能满足工程精度的要求 ,对地层热阻、环空隔热介质等的分析计算比较可靠。

The conventional method for calculating temperature distribution along the steam injection well bore has some shortcomings. A new model for finely describing temperature distribution along well bore was presented, and the corresponding software was programmed. The temperature outside of the insulating tube was determined with the local densification method. The calculation of temperature distribution in the main parts during the over-all heat transfer process in the axial direction was improved in consideration of the effects of the heat transfer process in the axial direction of collar, and the calculation approach for betterment of thermal resistance of the earth was improved. The overall heat transfer equations for the insulating tube were established. The numerical and analytical methods were employed to obtain temperature field. The new model has a good precision and can provide a reasonable prediction method for evaluating the efficiency of the steam injection system.