重力热管减少稠油井筒流体热损失

Two-phase closed thermosyphon(TPCT) decreases heat loss of liquid within heavy oil wellbores

考虑重力热管内汽液界面上剪切应力对液膜厚度和界面换热系数的影响,对井筒重力热管吸热段和放热段的平均换热系数进行了计算,进而对井筒重力热管流体热损失的计算方法进行了修正。同时通过室内物理模拟实验,对井筒重力热管流体热损失进行了实验测定,并着重分析汽液界面上剪切应力对流体热损失的影响规律。理论计算和室内实验表明,井筒重力热管除了能够调整井筒流体温度剖面外,还具有减小井筒流体热损失的作用;汽液界面上剪切应力对液膜具有向上携带的作用,具有增加液膜厚度和液膜导热热阻、从而减小井筒流体热损失的作用;井筒重力热管流体热损失受井筒流体温度和流体流量的影响,随流体温度的上升而增加,随流体流量的增加而减小。

Considering the effect of the shear stress of the steam-liquid interface in TPCT（two-phase closed thermosyphon） on the liquid film thickness and interface heat exchange coefficient,the average heat exchange coefficients of TPCT heat absorption interval and heat discharge interval were calculated to improve the calculation method of wellbore TPCT fluid heat loss.At the same time,through laboratory physical simulation experiments,the heat loss of wellbore TPCT was measured,and the influence rules of the shear stress of the steam-liquid interface on the fluid heat loss was analyzed.The theoretical calculation and laboratory experiments show that wellbore TPCT can not only adjust the fluid temperature profile in wellbore,but also decrease wellbore fluid heat loss;the shear stress on the steam-liquid interface has the effects to carry fluid film upward,it can increase fluid film thickness and fluid film heat conduction resistance,thus decreasing fluid heat loss in wellbore;wellbore TPCT fluid heat loss is affected by wellbore fluid temperature and fluid rate,increases with increasing fluid temperature and decreases with increasing fluid rate.