【作者】 王丹；

【导师】 李传宪； 杨飞；

【作者基本信息】 中国石油大学 ， 油气储运工程， 2011， 硕士

【摘要】 原油中已结晶蜡的量、蜡晶形态和结构是决定原油流变性的主要因素,热力和剪切条件也正是通过影响原油中蜡晶的形态和结构对宏观流变性产生影响的。本文结合理论基础和实验研究,对人工蜡油和含蜡原油蜡晶微观特性进行了较为全面的研究,并对人工蜡油和原油低温条件下的宏观流变性与蜡晶的微观特性之间的关系作了进一步的研究。本文主要利用差示扫描量热仪测量了不同含蜡原油原油降温过程中析蜡量与温度的关系,考察胶凝过程中含蜡原油的结晶放热特性,根据实验数据确定了不同温度下含蜡原油的析蜡量,并结合流变仪在小振幅振荡剪切的模式下,研究胶凝过程中含蜡原油储能模量、损耗模量、损耗角等流变参数的变化规律。通过流变学测量,结合差示扫描量热仪考察的胶凝过程中含蜡原油的结晶放热特性,探寻粘弹性参数与已析出的蜡晶质量分数的关系,建立微观结构分形维数与析蜡量、粘弹性参数的关系模型,间接获得含蜡原油微观结构的分形维数,从而建立了含蜡原油宏观流变性与蜡晶的微观特性之间的定量关系。此外,测量含蜡原油的屈服值,得出了原油屈服值与已析出的蜡晶质量分数满足指数关系。从而更深入地揭示含蜡原油的胶凝机理,希望能为含蜡原油加热管道输送工艺的安全、经济运行以及停输再启动提供理论依据。更多还原

【Abstract】 We all know that the content, the shape and the structure of the precipitated wax crystals are the major factors which are very important to crude oil rheology. The macroscopic rheological of crude oil is just affected by heat and shear conditions through affecting the shape and the structure of wax crystals. Therefore, Artificial waxy oil and crude oil’s microscopic characteristics are studied comprehensively in this paper combining with theoretical basis and experimental study. The relation between macroscopic rheological of crude oil and microscopic characteristics of wax crystals in the low temperature condition is also further studied in this paper. In this paper, the relation between wax content and temperature during cooling process of different waxy crude oil were mesured by Differential Scanning Calorimeter, the exothermic and crystallization characteristics of waxy crude oil during gelation process was investigated, and get the wax precipitation of waxy crude oil at different temperatures according to experimental data. Combined with the small amplitude oscillatory shear mode of rheometer, studied the storage modulus, loss modulus, loss angle changes during the gelation process of waxy crude oil. Through the rheological measurements, combined with the exothermic and crystallization characteristics of waxy crude oil during the gelation process, explore the relation between viscoelastic parameters and precipitated wax crystals. Established the relationship between micro-structure fractal dimension, the amount of wax precipitation and the the viscoelastic parameters, indirectly get the micro-structure fractal dimension of waxy crude oil, then established the relationship between macro-rheological properties of waxy crude oil and microscopic characteristics of wax crystals. In addition, measured the yield stress of waxy crude oil, indicated the exponential relationship between yield stress and precipitated wax crystals mass fraction. To deeply reveal the gelation mechanism of waxy crude oil, hoping to provide theoretical basis of safety, economic operation and the shutdown and restart for the heating pipeline transportation.更多还原