多元热流体在井筒中的流动与传热规律

Flow and heat transfer regulation of multi-thermal fluids injection in wellbore

建立高温烟气与水的热交换模型以及多元热流体在井筒内流动传热的温度场、压力场计算模型,计算含过热蒸汽和两相流状态的多元热流体在不同井深时的温度、压力以及其他参数。结果表明:随着井筒深度的增加,多元热流体的温度、压力均有所降低,并在某一深度多元热流体中水蒸气开始凝结,进入两相流状态,与纯蒸汽注入相比,其热损失量小,干度下降慢,在井底干度较大;井口注入温度越高、压力越小、流量越大,多元热流体的压降、温降幅度越大,热损失量越小;随着注入温度的降低,环空介质导热系数和注汽流量的增大,多元热流体干度的变化越早或过热度降幅越大,而注入压力对干度的影响有一个最优点,此时蒸汽在井底干度最大。

A heat transfer model between high temperature gas and water was established, and the wellbore temperature and pressure models calculating the temperature field, pressure field and other parameters of muhi-thermal fluids single phase flow and two phase flow were developed. The results show that the temperature and pressure of multi-thermal fluids reduce with the increase of the wellbore depth. And at a certain depth, the water vapor of multi-thermal fluids condenses into two phase flow state, and compared with the pure steam injection, the heat loss is small, dryness descends slowly and the bot-tom-hole dryness is high. The influence of annulus media on the decrease of temperature and pressure is small. The higher inject temperature, the smaller pressure and greater flow rate lead to the faster temperature and pressure declining, and the smaller heat loss. At the same time, the dryness of multi-thermal fluids changes earlier or degree of superheat drops greatly with the diminution of injection temperature, the increase of the annulus media heat conductivity and injection flow, but the influence of pressure on dryness has a best point, and the bottom-hole dryness is the highest.