Study On The Wax Crystals' Microscopic Characteristic Of Nan Yang Crude Oil

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, Nan Yang 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. The whole wax crystal's precipitation process which is along with decreasing temperature is observed by polarizing microscope in this paper. We obtain the characteristic curve of wax crystallization about waxy crude oil. The relation curve of viscosity and the precipitated area content of the wax crystal is explored by the rheometer. Then we establish quantitative relationship between macroscopic rheological of crude oil and microscopic characteristics of wax crystals. And we know that viscosity of crude oil and the precipitated area content of the wax crystal meet the index-style relationship. In addition, the new method which can describe the crystal image quantitatively is obtained by using fractal theory. That is to calculate the fractal dimension of wax crystal particles'distribution by using box-counting method. And the software which can calculate the fractal dimension of wax crystal image is developed. So as to we achieve the transformation from qualitative to quantitative. And we achieve a quantitative analysis by establishing quantitative relationship between macroscopic rheological of crude oil and microscopic characteristics of wax crystals. At last, Nanyang crude oil is dealed with different conditions according to several factors which affect the form of wax crystals in crude oil. The factors include thermal history, shearing history and adding the pour point depressant, etc. Then we obtain the characteristics of wax crystallization in different dealing conditions by observing the form and the structure of wax crystal with microscope. We hope these can play a guiding role to the low-temperature fluidity research about waxy crude oil.