Research On Crude Oil Physical Property And Distribution Discipline In Dongying Depress

The Dongying Depress is the most oil abundant depress in Bohai bay basin. Comparing with the exploration extent in this depress, a thorough study is still not carried out yet, especially in the horizontal and vertical variation of the crude oil property and its effect factors, fluid property and oil-gas reservoir. Therefore, carrying out the research on crude physical property as well as distribution discipline and finding out the main effect factors to the crude physical property will contribute to establish the theoretical foundation of the exploration, and to provide applicable parameters to the production of oilfield.On the basis of collecting and reviewing a lot of oil-gas testing and analysis data and some geochemical materials, by using a comprehensive research method, through carrying out the studies on the variation characters of crude oil physical-chemical property and analysis on the effect factors, we obtain the following knowledge:We classified the crude oil in Dongying Depression in two ways: physical property and oil source. From the point of view of the horizontal distribution, they all have a clitella character: in physical property, from the center to the border, the oil can be classified as light, medium, heavy and over-heavy oil; in oil source, it can be classified as Sha 3, Mixed, Sha 4.Crude oil properties in Dongying sag tend to change with burial depth. Relative density, viscosity, sulphur content, initial boiling point, and content of asphaltene plus colloid tend to decrease with the increase of reservoir depth, while solidifying point and paraffin content behave differently. There are certain correlations among different parameters describing physical property of crude oil. For example, there is an exponential relationship between relative density and viscosity, and viscosity will increase remarkably with the increase of relative density. Positive correlations exist between relative density and sulphur content, asphaltene plus colloid, and initial boiling point; while inverse correlation exists between relative density and paraffin content. Moreover,"S"type correlation exists between relative density and solidifying point.A clear cognition was established on the distribution discipline of the crude oil physical property in Dongying Depress. The distribution discipline was concluded both in horizontal and vertical dimension. In horizontal, the crude physical property is good in the depression, it is poor in the edge of the depression, and physical property variation is complex in the rift belt. In vertical, the crude oil physical property becomes better and better in depth, it has big differences in different layers, and it is not consistent even in the same layer.Through the analysis of the crude oil physical property, the main effect factors that cause the variation of crude oil physical property includes varied oil source, sedimentary environment, secondary variation and oil exploration and production, among which the effect from the oil source is very poor, and the secondary change of the crude oil physical property which is caused by the external environment is the main factor.