Research Of Structural Destruction Of Daqing Gelled Crude By Uniform Variabal Shearing

The most crude produced by the oil field has the character of high paraffin content、highviscosity、high condensation point and bad rheological property. With the temperaturedecreasing, the wax crystal would be separated out, and the lower temperature, the more waxcrystal. The three-dimensional net structure would be formed because of the gather andmutual crosslingding fo wax crystal. The liquid crude would be included by the net structureand the crude loss mobility as a whole. The gelled crude showed complicated rheologicalproperties, such as yield stress、thixotropy、viscoelasticity and so on. The research of gelledcrude theological properties has significant to the produce、transportation and use of the crude.The Theological properties of gelled crude is researched by the constant sheering rate, andmany scholars had the research on the theological properties. The text based on crudetheology, the uniform variable sheering is used to study the gelled crude theological propertiesunder different circumstances. The text studied that the variation of viscosity and viscosity to Daqing gelled crudesheared by uniform variabal shearing at the circumstances of thermal history、shearinghistory and different uniform variabal shearing. The different gelling strength sheared by uniform variabal shearing:the different rate oftemperature fall would result in different gelled structure. At the circumstances of uniformvariabal shearing, the strong gelled structure had a higher initial viscosity. With the shearingincreasing, the biscosity of different rate of temperature fall came near and tended to a stablevalue. Although the stresses were closer to each other, the stress increased with the sheer. Forthe different gelled temperatures, the viscosity and the stress had the different rules on theuniform variabal shearing process. The viscosities tended to a stable value, but the viscosity ishigh when the gelled temperature is low. Although the stress increase with the shear, the lowertemperature, the higher stress. The same gelling strength sheared by uniform variabal shearing:the rule is found that thehigh uniform variabal shear result in high viscosity and yield stress. With the shearing, theviscosities tend to a stable value, and the higher uniform variabal rate result in higherviscosities. The stresses increased with the shearing rate after second yield point, and higheruniform variabal rate, the higher stress.