Composition And Rheological Charaeteristics Of Typical Waxy Crude Oils In The Bohai Sea Area

Waxy crude oil components make the rheologic behavior of waxy crude oil very complicated at low temperature.Waxy crude oil is approximately Newtonian fluids at high temperature.When the temperature is below wax-melting point,wax will precipitate from the crude oil,waxy crude oil is Non-Newtonian fluids.Wax precipitation point,abnormal poin,gelling point,pour point and yield value appeared after temperature lowers continuously.The relationship of complicated rheologic behavior and chemical composition is indeterminate.Oil samples are come from engineering site at different waxy oil blocks in the Bohai Sea Area,and has different wax content.So the research results are more applied in engineering site.Oil samples pretreatment method based on national standard.Detect components,carbon distribution of wax and characteristic parameters of wax precipitation and rheologic with different methods,and compare different detecting methods.Analysis relationship of components and characteristic parameters with SPSS.The results indicated that wax precipitation amount pose greater influence to characteristic temperature than waxy content.Correlative analysis showed that there is a positive correlation between characteristic temperature and waxy content,and a negative correlation between characteristic temperature and wax precipitation amount.There is a negativ correlation between Wax precipitation point of DSC and waxy content of waxy crude oil which removing wax?resin and asphaltene.There is a positive correlation between viscosity of waxy crude oil in Newtonian fluids and resin content,and a positive correlation between viscosity of waxy crude oil in Non-Newtonian fluids and waxy conten? wax precipitation amount and asphaltene conten.There is no correlation between yield value at gelling point and components conten and wax precipitation amount.Liquid hydrocarbon?wax?resin and asphaltene components are extracted from waxy crude oil by alumina column chromatography method.Mixed wax with other components thoroughly to get samples.Wax precipitation process of sample is detected by differential scanning calorimetry(DSC).Comparison on the DSC curves to definite the effect of crude oil component on wax precipitation process.The results indicated that the interaction between crude oil components could inhibit wax precipitation process obviously.Liquid hydrocarbon?resin and asphaltene were all found to have inhibited wax precipitation process.The effect of liquid hydrocarbon topped the list,stronger than that of resin and asphaltene in order of potency.The wax precipitation point of sample containing liquid hydrocarbon decreased significantly,and the peak zone of wax precipitation change mildly.The wax precipitation point of sample containing resin and asphaltene is almost invariant.Resin and asphaltene decrease the crystallized paraffin amount in the highest peak zone of wax precipitation.