新疆油田吉7区掺水集油同沟敷设管道传热研究

发布时间：2018-08-27 16:42

【摘要】：新疆油田吉7区原油属于稠油,采用掺热水管道集油至中心站,再用拉油车送到联合站的集油工艺。集油管道采用的掺水管与集油管放在同一条管沟之内联合保温的敷设方式(联合保温),在运行中出现一些问题：如掺水管道温降较大,1.5km左右的掺水管道,最大温降曾达到24℃；设计过程中计算的结果不符,利用软件模拟温降仅为10℃,与实测数据相差14℃。对吉7区掺水管温降较大及管道终点计算不准确两个问题展开研究。基于传热学的相关理论,建立了掺水集油同沟敷设管道在分别保温(掺水管和集油管分别有各自的保温层,两条管道放在同一管沟内)、联合保温和复合保温(在联合保温的基础上,在掺水管与管间空气之间添加一定厚度的保温层)三种情况下的数学模型,采用保角变换的数学方法对模型进行求解。对于同沟敷设分别保温管道,推导了土壤温度场表达式、管道总换热系数和轴向温度分布解析表达式,在对计算结果进行验证的基础上分析了影响管道传热的因素。针对联合保温管道,推导出不考虑管间辐射换热情况下管道轴向温度计算的表达式；利用网络算法对管间辐射换热量进行计算,进而编写了考虑管间辐射换热时的沿线温度计算程序;分析了管道散热量和沿线温度分布在考虑和不考虑管间辐射换热两种情况下的差异,对两种情况下计算结果进行验证；分析了影响分别保温管道传热的因素。在总结分别保温和联合保温敷设方式特点的基础上,提出复合保温敷设方式并介绍其沿线温度分布的计算方法,分析了三种不同敷设方式对新疆昌吉油田的适用性。结果表明,利用分别保温沿线温度分布表达式计算的结果最大误差为0.58℃；在保温层较薄时,管道终点温度随着保温层的增加而升高,当保温层超过30mm时,再增加保温厚度对终点温度的影响较小；保温层为30mm时,沿线温度随着管道间距的增加而下降,但幅度极小；提高管道起始温度能在较大程度上提高其终点温度,对另一条管道沿线温度变化的影响较小；管道终点温度与管道埋深土壤温度呈线性关系。考虑辐射换热时,联合保温掺水管总散热量和集油管的吸热量均增大,掺水管辐射换热量占其向管间空气散热总量的9.8%,集油管辐射吸热量占其从管间吸热总量的33%,且管道终点温度在考虑辐射换热时的计算误差更小；随着保温层厚度的增加,两管终点温度均上升,上升速度随保温层厚度增加逐渐降低；提高掺水管起始温度能有效增加掺水管和集油管终点温度,掺水管起始温度每增加5℃,其终点温度升高3.4℃,集油管终点温度因沿线吸热量增加而升高0.7℃。分别保温辐射条件下,管道系统总散热量最多,但掺水管散热量较少；掺水管在联合保温敷设方式下的散热量明显偏高；复合保温敷设管道总散热量最少,且掺水管散热量也较低,较为适合新疆昌吉油田。
[Abstract]:The crude oil in Ji 7 area of Xinjiang oilfield belongs to heavy oil. It adopts the technology of gathering oil from the hot water pipeline to the central station, and then delivers it to the combined station by pulling oil truck. The maximum temperature drop of water-mixing pipeline about km was 24 C. The results of calculation in the design process were not consistent. The temperature drop simulated by software was only 10 C, which was 14 C different from the measured data.
Based on the theory of heat transfer, three kinds of conditions for laying pipelines with water and oil in the same ditch are established, which are respectively heat preservation (water pipe and oil pipe have their own heat preservation layer, two pipelines are placed in the same ditch), combined heat preservation and composite heat preservation (on the basis of combined heat preservation, a certain thickness of heat preservation layer is added between water pipe and air between water pipe). In this paper, the soil temperature field, the total heat transfer coefficient and the axial temperature distribution are deduced, and the factors affecting the heat transfer of the pipeline are analyzed on the basis of verifying the calculation results. The expression of the axial temperature of the pipe without considering the radiation heat transfer between pipes is deduced. The network algorithm is used to calculate the radiation heat transfer between pipes, and then the temperature calculation program considering the radiation heat transfer between pipes is compiled. The difference of heat transfer between two cases is verified, and the factors affecting heat transfer of insulation pipes are analyzed. On the basis of summarizing the characteristics of insulation laying and combined insulation laying, the composite insulation laying method is put forward and the calculation method of temperature distribution along the line is introduced. Three different laying methods are analyzed. The applicability of the method to Xinjiang Changji oilfield.
The results show that the maximum error is 0.58 Increasing the initial temperature of the pipeline has little effect on the temperature variation along the other pipeline; the terminal temperature of the pipeline has a linear relationship with the soil temperature of the pipeline buried depth. With the increase of the heat transfer rate, the radiant heat transfer rate of the mixing pipe accounted for 9.8% of the total heat transfer rate to the air between the pipes, and the radiant heat absorption rate of the oil collector pipe accounted for 33% of the total heat transfer rate between the pipes. Increasing the initial temperature of the mixed water pipe can effectively increase the terminal temperature of the mixed water pipe and the oil collecting pipe. The terminal temperature of the mixed water pipe increases by 3.4, and the terminal temperature of the oil collecting pipe increases by 0.7. The total heat dissipation of the pipes with composite insulation laying is the least, and the heat dissipation of the pipes with composite insulation laying is also lower, so it is more suitable for Changji Oilfield in Xinjiang.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE832

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