海底含蜡原油管道蜡沉积与清管周期研究

发布时间：2018-05-30 19:33

本文选题：含蜡原油 + 蜡沉积　；参考：《西南石油大学》2015年硕士论文

【摘要】：含蜡原油在海底管道中输送时,蜡沉积是影响管道安全运行的重大隐患。研究含蜡原油在海底管道中的蜡沉积规律,并制定出经济合理的清管周期,既能保证管道安全运行,又能促进企业降本增效,具有重要的社会和经济效益。本研究以与某海上油田的科研合作项目为依托,是该项目的核心研究内容。本文采用环道实验与计算机模拟相结合的研究手段,对海底含蜡原油管道蜡沉积规律及清管周期进行研究。首先,测试含蜡原油及其掺稀油的物性参数及流变特性；其次,根据现场条件确定用于室内环道蜡沉积实验的油样和主要实验参数(如管输流量、输送温度等)；接着,设置与实验条件一致的蜡沉积模拟参数,运用PVTSim软件中的蜡沉积模块(DepoWax模块)进行蜡沉积模拟,对比分析模拟结果与实验数据；然后,运用DepoWax模块模拟东海海底管道在运行过程中的蜡沉积现象,分析蜡沉积规律,找出蜡沉积高峰段和主要影响因素；最后,以输油动力消耗与清管费用为目标函数建立清管周期模型,通过Visual Basic编程语言编写海底原油管道最优清管周期计算程序,并分析输油温度、管道输量对清管周期和运行成本的影响。对实验油样的流变特性分析表明：油样掺稀后,反常点、析蜡点均下降,油品的低温流动特性变好。蜡沉积环道实验运行约4h后,管壁上开始出现少量蜡沉积,之后随着运行时间的增长,结蜡厚度不断增加,增长速率总体表现出先快后慢的趋势,且流体温度越高,该趋势越明显。DepoWax模拟结果与环道实验数据对比发现：实验条件下管壁蜡沉积层的蜡分子孔隙度在80%左右,模拟结果与实验结果所表现出来的规律性基本一致,验证了模拟的有效性。东海海底管线的蜡沉积模拟结果表明：入口流体温度越高,油样掺稀比越大,管线中最先出现蜡沉积的位置以及析蜡高峰区越靠后；管输流量越大,蜡分子孔隙度越大,管壁结蜡厚度越大。以BYT至平湖DPP管道为例,对海底管道在不同输送条件下的最优清管周期进行了计算分析,结果表明：最优清管周期随输油起点温度升高而增大,随输量增大而减小；输油运行成本随输油温度升高而降低,随输量增大而增大。
[Abstract]:When waxy crude oil is transported in submarine pipeline, wax deposit is a major hidden trouble affecting the safe operation of pipeline. The waxy deposit of waxy crude oil in submarine pipeline is studied, and the economical and reasonable cleaning period is worked out, which can not only guarantee the safe operation of pipeline, but also promote the enterprise to reduce the cost and increase efficiency, which has important social and economic benefits. This research is based on the scientific research cooperation project with an offshore oil field and is the core research content of this project. In this paper, the wax deposition law and pipe-cleaning period of waxy crude oil pipeline are studied by means of loop experiment and computer simulation. First, the physical properties and rheological properties of waxy crude oil and its dilute oil are tested. Secondly, the oil samples and main experimental parameters (such as pipe flow rate, transportation temperature, etc.) used for the laboratory annular wax deposition experiment are determined according to the field conditions. Setting the wax deposition simulation parameters consistent with the experimental conditions, using the wax deposition module in PVTSim software (DepoWax module) to carry out the wax deposition simulation, comparing the simulation results with the experimental data; then, DepoWax module is used to simulate wax deposition in the course of operation of the submarine pipeline in the East China Sea, to analyze the wax deposition law, to find out the peak section of wax deposition and the main influencing factors. Based on the objective function of power consumption and pipe-cleaning cost, the pigging cycle model is established, and the optimal pigging period calculation program of submarine crude oil pipeline is compiled by Visual Basic programming language, and the oil transportation temperature is analyzed. The influence of pipeline volume on pipe-clearing cycle and operation cost. The rheological characteristics of the experimental oil samples are analyzed. The results show that the abnormal point and wax precipitation point of the oil sample decrease and the flow characteristics of the oil at low temperature become better when the oil sample is dilute. A small amount of wax deposition began to appear on the pipe wall after 4 hours of experimental operation of wax deposition loop, and then, with the increase of operation time, the wax deposition thickness increased, and the growth rate showed the trend of first fast and then slow, and the higher the temperature of the fluid, the higher the temperature of the wax deposit was. The more obvious the trend is, the more obvious the simulated results of DepoWax are compared with the experimental data of the annular channel. It is found that the wax molecular porosity of the wax deposit layer of the tube wall is about 80% under the experimental conditions, and the simulation results are basically consistent with the experimental results. The validity of the simulation is verified. The simulation results of wax deposition in the submarine pipeline of the East China Sea show that the higher the inlet fluid temperature, the greater the blending ratio of oil samples, the more the position of wax deposition first appears in the pipeline and the lower the peak area of wax evolution is, and the larger the pipe flow rate is, the greater the porosity of wax molecules is. The thicker the pipe wall wax deposit is. Taking the BYT to Pinghu DPP pipeline as an example, the optimal pigging period of the submarine pipeline under different transportation conditions is calculated and analyzed. The results show that the optimal pigging period increases with the increase of the starting temperature of oil transportation and decreases with the increase of the transportation quantity. The operating cost of oil transportation decreases with the increase of oil temperature and increases with the increase of oil transportation volume.
【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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