油井传热瞬态导热函数的高精度近似解

High precision approximate solution of transient heat-conduction time function of wellbore heat transfer

瞬态导热函数是注蒸汽油井热采过程中分析井筒传热的关键函数。目前常用的的瞬态导热函数以及相应的近似解都忽略井筒热容等参数的影响,但在注汽时间较短时井筒热容对传热影响很明显,因此在注蒸汽初期误差较大。新的瞬态导热函数近似解是在考虑了井筒热容的瞬态导热函数的基础上建立的,可以更好地适用于注蒸汽初期。研究结果表明,新的瞬态导热函数近似解形式简单、应用方便,比传统的近似解具有更广的适用性和更高的计算精度,因此有较好的工程实用性。

Transient heat-conduction time function is a crucial function for wellbore heat transfer in the process of steam injection for heavy oil production.All of the common transient heat-conduction time functions and related approximate solutions ignore wellbore heat capacity and other properties,but the heat capacity has obvious effect on the heat transfer in wellbore,especially in short time,so the error is large in the early days of steam injection.Based on a novel transient heat-conduction time function considering the effect of heat capacity of wellbore,a new approximate solution is obtained by the numerical fitting method and compared with those traditional approximate solutions,which only give good results in long time.The new approximate solution presents higher precision all the time,especially in the early period of steam injection.It is shown that the new approximate solution of transient heat-conduction time function is simple in form and easy to use,so it has good practicability in engineering with wider applicability.