【作者】 马华伟；

【导师】 何利民；

【作者基本信息】 中国石油大学 ， 油气储运工程， 2008， 博士

【摘要】 在海洋石油开采过程中,严重段塞流是多相混输管道中一种有害现象,对其进行深入的研究具有重要的理论和实际意义。本文在内径为0.051m的下倾管-立管、增加气体缓冲空间的下倾管-立管、垂直下降管-下倾管-立管和下倾管-柔性立管共4套实验管段上对空气-水严重段塞流进行了深入、系统地研究,揭示了严重段塞流的产生机理和流动特性,提出了采用旁通管消除严重段塞流的一种新方法,并进行了实验验证。主要研究内容和结论如下:对4套实验管段上严重段塞流的流型图进行了对比研究和分析,发现严重段塞流的发生区域与实验管段的布置形式有关,主要受下倾管倾角和立管前气体积累空间的影响。下倾管倾角为0°时,严重段塞流的发生区域远小于-1°～-4°时。下倾管倾角介于-1°～-4°时,倾角的变化对严重段塞流发生区域的影响很小。立管前气体积累空间的大小对严重段塞流的发生区域有较大影响,严重段塞流的发生区域随气体积累空间的增加而增大。B?e判别准则预测的严重段塞流发生区域小于实验结果,本文推导了新的严重段塞流发生区域判别式,能更准确的预测严重段塞流的发生区域。对4套实验管段上严重段塞流的流动特性进行了实验研究和分析,发现实验管段入口处的气、液相折算流速、立管前气体积累空间对严重段塞流的流动特性产生较大影响,下倾管倾角对其影响很小。严重段塞流具有严格的周期性,周期长度随气相折算速度、液相折算速度和下倾管倾角的增加(从-4°到-1°)而减小。严重段塞流的压力波动幅度随气、液相折算流速的改变而变化,压力波动幅度的最大值出现在严重段塞流流型Ⅰ和过渡流型Ⅱ的转换边界上。对增加气体缓冲空间后下倾管-立管实验管段上严重段塞流的实验研究发现,当液相流量较大时,液气喷发阶段高速流动的气相将下倾管内液体吹起形成气速诱导液塞。气速诱导液塞会对立管底部产生很大的冲击,同时会对严重段塞流的周期特性产生影响。通过对下倾管-柔性立管实验系统中严重段塞流的循环过程进行了分析,指出了液气喷发阶段和液塞形成阶段液塞运动的两个步骤。根据实验中观察到的各实验管段内气、液两相的流动特点,建立了包含气体缓冲空间的下倾管-立管实验系统和下倾管-柔性立管实验系统中的严重段塞流模型,并将数学模型的计算结果与实验数据进行了对比。结果表明,该数学模型能够比较准确的描述出实验管段上严重段塞流的循环过程,并且得到严重段塞流的周期长度、液塞速度等特征参数。在有、无气体缓冲空间的下倾管-立管实验管段上,对旁通管法消除严重段塞流的效果进行了实验研究,并对有气体缓冲空间的下倾管-立管实验管段上采用旁通管消除严重段塞流的方法进行了改进。研究发现,实验管段开旁通管后会缩小严重段塞流的发生范围,特别是严重段塞流流型Ⅰ的范围显著缩小。当旁通管完全消除严重段塞流后,改变液量对旁通管的消除效果没有影响。旁通管的存在会减弱严重段塞流的压力波动幅度。根据旁通管和下倾管-立管实验管路的压力平衡,提出了旁通管法消除严重段塞流的稳态数学模型。使用这个数学模型可以指导旁通管的设计和调节阀的控制,实现严重段塞流的消除。更多还原

【Abstract】 Severe slugging phenomenon is commonly encountered in multiphase pipeline of offshore petroleum exploitation system. In this study, the severe slugging phenomena in decline-riser test pipe, decline-riser test pipe with addition gas volume, plummet-decline-riser test pipe, and decline-flexible riser test pipe were studied systematically. The inner diameter of test pipe is 0.051m. The mechanism and flow characteristics of severe slugging phenomenon were analyzed. A bypass-pipe method for eliminating severe slugging was developed and verified with the experiments. The main contents and conclusions are as follows:The flow pattern maps of severe slugging in 4 sets of test pipe were studied and compared. It was found that the occurring range of severe slugging depends on the layout of test pipe. The decline angle and the gas volume of pipe before riser pipe influence the occurring range of severe slugging. The occurring range of severe slugging in 0°decline pipe is smaller than that of -1°～-4°. When decline angle is between -1°and -4°, the influence of decline angle on the occurring range of severe slugging is very weak. With the gas volume of pipe before riser pipe increasing, the occurring range of severe slugging expands. the occurring range of severe slugging predicted by B?e equation is smaller than experimental results. A modified equation was developed.The flow characteristics of severe slugging in 4 sets of test pipe were studied and compared. It was found that the influences of gas superficial velocity, liquid superficial velocity and the gas volume of pipe before riser pipe on flow characteristics of severe slugging are obvious, but the influence of decline angle is weak. Severe slugging phenomenon have strict period characteristic. The length of period decreases with gas superficial velocity, liquid superficial velocity and decline angle (-4°~-1°) increasing. The pressure fluctuation of severe slugging depends on gas superficial velocity, liquid superficial velocity and the gas volume of pipe before riser pipe. The maximum value of pressure fluctuation occurs at the boundary of SS I and SS II. The experimental studies of severe slugging in decline-riser pipe with additional gas volume were carried out extensively. At higher liquid superficial velocity, the abduction slug of gas velocity was found. The abduction slug impacts on bottom of riser pipe heavily and influences the period characteristic of severe slugging. By analyzing the flow characteristic of severe slugging in decline-flexible riser pipe, two steps of blowout stage and slug formation stage were described.Based on the mass conservation of gas and the momentum conservation of the liquid in the pipeline, a mathematics model of severe slugging in decline-riser pipe and decline-flexible riser pipe with additional gas volume was developed. The mathematics model was verified by comparing the results of experimental and model. It was found that the model fit well to experimental result. The model can precisely predict the characteristic of severe slugging such as period, slug velocity etc.A bypass-pipe method for eliminating severe slugging was developed and verified with the experiments. The bypass-pipe method was modified to eliminate the severe slugging in decline-riser pipe with additional gas volume. It was found that the occurring range of severe slugging, especially the SS I, become smaller when bypass-pipe opened. Liquid superficial velocity has little influence on effect of bypass-pipe method. A mathematic model was educed using the pressure balance of bypass-pipe and riser pipe. The model can carry out the design of bypass-pipe and the control of adjust valve.更多还原