【作者】 王栋；

【导师】 赵宗昌；

【作者基本信息】 大连理工大学 ， 化学工程， 2005， 硕士

【摘要】 我国大多数油田开采的原油为石蜡基原油,其凝点和反常点温度较高,流变性质异常复杂。当原油温度逐渐降至凝点附近时,其流变性质表现出复杂的触变性。传统上多采用加热工艺进行原油的管道输送。为了降低运行成本,提高管道运行的经济性,常温输送是管输含蜡原油的发展趋势。因此对含蜡原油低温流动特性及其管输特点进行深入的研究是十分必要的。 在原油的储运和加工过程中常常出现蜡的沉积,这引起原油表观粘度的增加,会给管输过程带来许多麻烦和危险。因此,全面研究含蜡原油的流变性质,尤其是较低温度下的流变性质,对原油工业是非常重要的。 本论文以大庆外输含蜡原油为油样,对含蜡原油的流变性质进行了较系统的实验研究。并重点对凝点下的触变性进行了实验研究,利用实验数据获得了不同温度下描述其初次裂降过程的R-G模型方程中的模型参数,对模型中的参数与温度的关系进行了曲线拟合,得到各参数与温度的关系。计算结果与实验数据吻合良好。实验还发现含蜡原油降温速率对其触变性有着重要的影响,降温速率越大,屈服应力和平衡应力越高。 对加剂原油的流变性质也进行了流变实验研究,对降凝机理进行了讨论。运用偏振光显微镜对加剂与不加剂原油的蜡晶结构进行了大量的显微观察,采集了蜡晶图像,利用特征提取软件得到其特征的量化参数,讨论了微观蜡晶的形态和结构对宏观流变性质的影响。还尝试运用分形理论对蜡晶图像进行定量描述,为今后进一步从定量的角度建立原油流变性质机理模型、研究原油宏观流变性质与微观蜡晶形态与结构的关系探寻了方向。更多还原

【Abstract】 The crude oils exploited in our country’s oilfields are mainly waxy crude oil, which have high solidification point and abnormal point and shows most complex rheology. When the temperature drops and approaches the solidification point, it will has the thioxtropy. Traditionally the pipeline transportation of crude oil is done in the calefaction technique. To decrease the cost of transportation and make its more economical, the pipeline transportation at the normal temperature will be developed. So the throughout research to the flow behavior of crude oil at low temperature and its characteristic in the pipeline is most necessary.The deposition of wax often appears in the storage, transportation and production, which can result in the increase of apparent viscosity of oils, and this may cause much severe problems and dangers in the pipeline transportation. Hence, the throughout research to the rheological behavior of wax crude oil, especially at the low temperature, is very important to oil industries.hi this paper, Daqing forth transportation wax crude oil is use as an experimental sample, and a series of experiment have been designed and finished to study the rehology of waxy crude oil. More important, some experimental research has been performed to find out the thixotropy of Daqing crude oil under the solidification point. Based on the experimental data, we have gotten all the parameters in the R-G equation, used to characterize the curve of firstly breaking up and decaying stress of the waxy crude oil at different temperatures. We have also studied and acquired the relationship between these parameters and temperature. The calculation results agree with the experimental data well. It has been find out that cooling rate has great influence on thixotropy in the experiments and as cooling rate getting higher yield stress and equilibrium stress will both be larger.We has also done the experiment research on the rheology of waxy crude oil with depressant and discuss the mechanism of depressant. The morphology of paraffin crystals in crude oils and crude oils with depressant has been observe by the polarized microscopy. We have gotten many photos and acquired some quantitative parameters to characterization the paraffin crystals by some software, and discussed the relationship between the morphology and configuration of paraffin crystals and rheology of crude oil. We have used fractal theory to characterize the morphology and configuration of paraffin crystals quantitatively. This point out a new way to further make the quantitative mechanism model of rheology of crude oil and relationship between rheology and morphology or configuration of paraffin crystals of crude oil.更多还原