井筒注汽过程隔热油管传热性能实验分析

稠油热采过程中，热流体由隔热油管组成的管柱注入油层。隔热油管是减少热流体在注入过程中散热损失并保护套管的关键部件，目前国内外学者对隔热油管热损失的研究，多集中在理论分析和数值计算研究方面。隔热油管由内管、隔热层和外管组成，其绝热效果取决于隔热层的视热导率。通过设计和研制的隔热油管地面模拟实验装置，测定了隔热油管的表面温度与热流分布；根据实测数据分别计算了较新隔热油管与较旧隔热油管的视热导率。实验分析发现，接箍与隔热油管外壁之间存在热桥，受影响的隔热油管长度约为0.5 m；接箍处的热通量高于正常隔热油管的3倍以上；较旧隔热油管视热流、表面温度和视热导率明显高于较新隔热油管，隔热性能下降。根据目前隔热油管的生产工艺和结构特点等提出了改进隔热性能的几点建议。

Experimental analysis of heat transfer performance of thermal insulated tubing for steam injection in wellbore

In the process of thermal recovery of heavy oil, hot fluid is injected into oil reservoir through pipe strings made up of thermal insulated tubing. Thermal insulated tubing is the key component to reduce heat loss and to protect tubes in the process of hot fluid injection. Currently the researches on heat loss of thermal insulated tubing by domestic and foreign scholars mainly focus on theoretical analysis and numerical calculation. Thermal insulated tubing consists of interior tube, thermal insulating layer and exterior tube, its thermal insulated effect depends on the apparent heat conductivity of thermal insulating layer. This paper designed and developed ground analogue test device of thermal insulated tubing and actually measured the surface temperature hot fluid distribution with device, then calculated the apparent heat conductivity of new and old thermal insulated layer based on experimental date. The study result shows that: heat bridge existed between the collar and exterior of insulated pipe, and the affected length of insulated pipe is about 0.5 m.Heat flow rate in the normal insulated pipe is less 3 times than that in the heat density of collar. The apparent hot flow, surface temperature and apparent heat conductivity of oldthermal insulated tubing is obviously higher than those of new thermal insulated tubing, and the thermal insulated performance in the old insulated tubing decreases. According with current manufacture technique and structure characteristics of thermal insulated tubing, some suggestions are proposed for improving thermal insulated performance.