注蒸汽井筒热损模拟实验及改进设计研究

HEAT LOSS EXPERIMENT OF STEAM INJECTION WELLBORE AND ITS IMPROVED DESIGN

稠油开采主要以注蒸汽热采为主,蒸汽沿井筒流动过程中,井筒散热损失和蒸汽温度、干度等均沿流程变化,对其进行精确计算和分析,对油田提高采收效果具有重要意义。本文对井筒结构和传热过程进行了分析,通过地面模拟实验,实测了隔热管的热损分布,并提出了热损合理分布概念。研究发现,接箍和隔热管外壁存在热桥,受影响的隔热管长度在0.5 m左右.同时,接箍处热流密度是正常隔热管的3倍以上,是需要研究的重点。按热损合理分布概念提出了三套改进设计方案,并对其进行了对比分析.

Heavy oil recovery is mainly used thermal recovery by steam injection. In the steam flow process along the wellbore, wellbore heat loss, steam temperature and steam dryness all change with the process. If these parameters can be calculated and analyzed precisely, it has important significance on enhanced oil recovery. This paper analyses the wellbore structure and the heat transfer process of wellbore. According to ground simulation test, the actual heat loss distribution is measured, and then the concept of reasonable heat loss distribution is presented. The research shows that： there are heat bridge between casing collar and insulated tubing; the affected length of insulated tubing is about 0.5 meter. And the heat flux of casing collar is three times more than the normal collar which is the key that need to be studied. Based on the concept of reasonable heat loss distribution, three sets of improvement design scheme are proposed, and comparative analysis is carried out.