双水平井SAGD预热阶段温度场计算

Calculation of temperature field in SAGD preheating stage of double horizontal wells

中文关键词: 水平井  蒸汽辅助重力泄油  流函数  数值方法  非结构化网格

英文关键词: horizontal well  steam assisted gravity draining,SAGD  stream function  numerical methods  unstructured grid

中文摘要:

      采用满足质量守恒的流函数方法,编制有限容积法程序,模拟计算了双水平井SAGD蒸汽循环启动预热阶段温度场演化情况。对比了纯导热机理与导热及热对流共同作用的差别,给出了单位长度井散热速度和两井中间位置温度随时间的变化,同时,也分析了井间距对预热时间的影响。结果表明,单位井长度的散热速度逐渐减少,在初始阶段变化较快,然后以较慢的速度降低。以恒热流为加热条件的温度叠加分析方法,预测热联通需要的加热时间是不合适的。影响预热时间的主要因素为两井间距,大约间距扩大一倍,预热时间延长为原来的4倍左右；原油粘度很大且随温度变化不太敏感或井间距较小的情况,自然对流换热作用很弱,在预测预热时间时可以按照纯导热模型处理,而相对不太粘稠的原油或井间距较大时热对流作用强,不能忽略对流传热的影响,自然对流换热可大大缩短预热时间。

英文摘要:

      The temperature field evolution of SAGD steam cycle of doube horizontal wells is simulated using the stream function method. The difference between the pure thermal conduction effect and the effect of heat conduction coupling with convection is compared.The heat dissipation rate of unit length and the change of the temperature in the middle of the two wells with time are given.Besides, the influence of wells pacing on preheating time is also analyzed.The final results show that the heat dissipation rate of unitl ength is larger in the initial stage,but decreases quickly and graduallyr eaches are lativelystablevalue.The main factor affecting the preheating time is the well spacing,and the preheating time is 4 times of the original one when the wells pacingis doubled.The natural convection heat transfer effectis very weak when the viscosity of crude oil is large or the well spacing is small, while it becomes strong when the viscosity of crude oil is not very large or the well spacing is large. For the latter case,the preheating time is substantially reduced.