Abstract: The comprehensive analysis of in-place oil viscosity-temperature curves and oil analysis data aims at deepening the understanding of crude physical property. The study shows that the crude oil viscosity-temperature curves from different oil fields, different horizons and different well depths have good fractal feature. Under the fractal conditions that we regard viscosity as scale and temperature as object, the fractal dimension D is decimal, and the numerical value ranges from 0.1 to 0.3. With increase of the fractal dimension, the effect of temperature on viscosity becomes smaller. The fractal dimension and the parameters such as density, viscosity and initial boiling point of crude oil have good correlativity. So the fractal dimension D can be taken as a new characteristic parameter reflecting crude oil physical properties. It is only related with asphaltene content, rather than wax content and gel content, showing that the asphaltene and its content is the main factor influencing fractal dimension value of crude property and viscosity-temperature curve. This conclusion is accordant with the viewpoint that asphaltene fraction takes principal part in changing wettability of rocks, compared with other fractions.

Key words: fractal theory, fractal dimension, in-place oil, viscosity, temperature, viscosity-temperature curve, asphaltene