Research On Reological Property Of Live Oil And Establishment Of Reological Model

Solubility and rheological behaviors of the saturated live crude oil were studied in detail in the paper,based on gas/liquid equilibrium theory,thermodynamics theory,crude oil rheology theory and its measuring technique.⑴Using the self-developed field sampling device,freezing point measuring device,solubility and rheology measuring device,the solubility properties and rheological properties of Chang 6 and Chang 8 live oil were researched.Through a lot of results were derived from the experiment.(1)Solubility: As the increase of the pressure,the solubility of saturated live oil increased.And as the increase of the temperature,the solubility showed a trend of first increasing and then decreasing.(2)Freezing point: As the increase of the heating temperature,the freezing point of the live oil showed a trend of first decreasing and then tended to be the same,and the inflection point of the heating temperature is 70℃.Meanwhile,as the increase of the pressure,the freezing point of the live oil decreased.In addition,at the low temperatures,the shearing action for crude oil made the wax crystal be difficult to form space grid structure.It resulted in the decrease of freezing point of crude oil.(3)Viscosity: Firstly,with different heating temperature,the viscosity of crude oil under non-Newtonian fluid and abnormal point changed a lot and the viscosity of crude oil under Newtonian fluid and wax precipitation point had no effect.Second,as the increase of the pressure,the viscosity of live oil decreased and the viscosity reduction rate increase with the increase of dissolved gas.At the same time,the wax precipitation point and abnoraml point decreased.Additionally,the shearing action for the crude oil under non-Newtonian fluid led to the deterioration of crude oil rheology and increased the viscosity of the crude oil at low temperature.(4)Yield value: When the temperature is lower,with the increase of the pressure,the increase of the dissolved gas inhibited the precipitation of wax crystal and made the live oil yield value rise at a slower pace.⑵Establishing the model of viscosity and solubility of live oil on the basis of the existing data,the results show that the difference between calculated values and experimental values is less,the error is about 10% which is in the scope of the project permission,and the model can be used for practical engineering.Through the above research work which had been done,the gas-dissolved property and rheological property are revealed.It provided a theoretical basis for the gathering oil without heating with Changqing live oil.