【作者】 李玉春；

【导师】 刘扬；

【作者基本信息】 东北石油大学 ， 油气储运工程， 2011， 博士

【摘要】 海拉尔油田针对“偏、远、散、寒”的特殊地理环境特点,结合不同区块开发的实际情况,灵活地采用了“提、拉、掺、树、混”等集油工艺,并于2009年实现了原油管道外输。集输系统原油含水率在转相点附近时,管内介质的粘度会急剧增大,从而带来井口回压急剧上升,会给油井及集油系统带来危害；部分输油管道投产以来出现了比较严重的结蜡现象,加之输量较低及运行输量波动较大的影响,使外输油干线实际运行时摩阻快速上升,直接影响到输油管线的安全运行。因此,有必要从调查管道的历史运行参数、分析各站点的运行方案及其调整情况出发,研究海拉尔集输油管道运行存在的问题、成因及潜在风险,提出合理的集输油运行方案及建议措施。本论文的主要研究内容包括：(1)分析海拉尔油田含水原油不同温度、剪切速率下的粘度随含水率变化规律,研究确定出各区块含水原油乳化体系的转相点,以此给出双管掺水、环状掺水及电加热等集油工艺的包括含水率、集油温度等的适应性指标体系,并提出当集油系统原油含水率达到转相点附近时的解决措施。(2)测定净化外输油的密度、比热容、凝固点、含蜡量、胶质、沥青质含量及全粘温曲线,给出海拉尔油田各区块净化油的基础物性及粘温性质；以净化外输油剪切速率与剪切应力的变化关系及剪切速率与粘度的变化关系为基础,确定原油的流变指数、稠度系数、屈服值等流变特征参数；测定净化外输油的析蜡点、反常点及析蜡峰温,试验得出温度对外输油析蜡量及比热容的影响规律。(3)结合海拉尔外输油管道运行现状,针对蜡晶颗粒的溶解、析出、聚集及其空间网状体结构的恢复与形成机制,通过考察凝点指标的变化,实验研究热作用、剪切作用对外输油流动性能的影响；分别考虑海拉尔油田实际运行中不同净化油的混合比例及性质差异较大的两种油品的变比例混合,测试混合油基础物性、粘温特征参数及流变特征参数,研究分析掺混对原油流动性的影响。(4)根据差压法原理,建立测定海拉尔原油蜡沉积速率室内模拟试验装置,在确定不同流态区管壁处剪切应力、管壁处蜡分子浓度梯度、管道沿线温降分布及径向温度梯度的基础上,覆盖各种典型工况条件(包括温度梯度、流速等)开展管输原油蜡沉积模拟试验,并根据各相关参数的确定方法及模拟试验数据,回归建立适合海拉尔原油管道的蜡沉积速率模型。(5)分析热油管道的“管道特性允许最小输量”和“热力条件允许最小输量”的区别与联系,指出管道实际运行的允许最小输量应是它们中的较大值。在计算确定海拉尔油田各输油管道允许最小输量的基础上,结合开发部门的产能预测,从添加降凝剂、热处理改性、加水输送、增加中间加热站、正反输运行等保证含蜡原油管道低输量安全运行的常规方法中,优选适合于每条管道的设计调整方案,并给出相应的主要工程量。更多还原

【Abstract】 According to the characteristics of special geographical environment, such as’remote, far, scatter, cold’, and combined with the actual situation of different blocks development, the oil gathering process of’raise, pull, blend, dendroid, mix’was adopted in Hailaer Oilfield, and the pipeline transportation of crude oil was realized in 2009. When the water content of crude oil in gathering system is near the phase transition point, the medium viscosity in tube will increase dramatically, then lead to a sharp rise of wellhead back pressure, and bring harm to oil wells and gathering system. Some pipelines have come out the serious phenomenon of wax deposition since operation, and coupled with effects of lower transmission capacity and much rate fluctuation, which makes pipelines route friction on the rapid rise with the actual operation, and the safe operation of pipeline is affected directly. Therefore, it is necessary to start from surveying the history operating parameters of the pipeline and analyzing the all site’s operation scheme and adjustive conditions to research the existing problems, causes and potential risks of the Hailaer oil gathering and transporting pipeline in operation, and then the reasonable operation scheme and measures of setting oil is put forward.The main contents of this paper include:(1)Analyze the law of viscosity with water ratio variation under different temperature and shear rate for water cut oil of Hailaer Oilfield, determine the phase transition point of watered cut oil emulsification system for each block, thus the adaptability index system including water ratio, oil gathering temperature, etc. for double-tube with water, circular tube with water and electrical heating oil gathering process is provided. And also the solutions are put forward when water ratio reaches the phase transition point of oil gathering system.(2)Test the density, specific heat capacity, freezing point, wax content, colloid, asphaltene content and full viscosity-temperature curve of exported purification oil, thus the foundamental physical property and viscosity-temperature properties of purification oil for each block in Hailaer Oilfield are given out. The rheological characteristic parameters such as rheological index, consistency coefficient and yield value are ascertained on the basis of the variation relationship between shear rate and shear stress, between shear rate and viscosity for purification oil. Test wax precipitation point, abnormal point and wax precipitation peak of purification oil, the influence law of temperature on wax precipitation amount and specific heat capacity is got through experiment.(3)Combined with the current situation of oil pipeline in Hailaer, to counter the dissolution, precipitation, aggregation of wax particle and the recovery and formation mechanism of its spatial network structure, the influence of thermal effect and shear effect on the flow property of exported is studied through experiment by investigating the changes of solidification point. Considering the mixture ratio of different purification oil and the variable mixing ratio of two kinds of oil that have quite different properties respectively during actual operation of Hailaer Oilfield, the influence of mixing on crude oil flowability is studied through determination the basical physical properties, viscosity-temperature feature parameters and rheological parameters of the mixed oil.(4)According to the principle of differential pressure method, the indoor simulation experiment device of wax deposition rate for Hailaer crude oil is set up. Based on the determination of pipe wall shearing stress, wax molecular concentration gradient at pipe wall, temperature drop distribution along pipeline and radial temperature gradient for different flow pattern, the wax deposition experiment of oil transferring pipeline which covers all the typical working conditions including temperature gradient, flow velosity etc. is developed. And the wax deposition rate model for the crude oil pipeline in Hailaer is established on the basis of the determining method for the related parameters and the simulation experiment data.(5)The difference and relation between two kinds of allowed minimum transportation amount of hot oil pipeline, namely ’the allowed minimum transportation amount of pipeline characteristics’ and ’the allowed minimum transportation amount of thermal condition’ is analyzed, and it is pointed that the allowed minimum transportation amount of the actual pipeline in operation should be the higher one. Based on the calculation for the allowed minimum transportation amount of various pipelines in Hailaer Oilfield, combined with the productivity prediction of development department, the suitable design adjustment scheme for every pipeline is selected from the conventional method of ensuring the safe operation of low transportation amount in waxed oil pipeline, including the addition of pour point depressant, modification of heat treatment, blending water transportation, increasing the number of middle heating stations, operation of positive and negative transportation, etc., and also the corresponding major projects is given.更多还原