Study On The Influence Pattern Of Nano Pour Point Depressant And Magnetic Field On Yield Stress Of Waxy Oil

Crude oil produced in China contains a large proportion of waxy crude oil.The waxy crude oil has the characteristics of high gel point and poor low-temperature fluidity.During the storage or transportation of crude oil,the temperature falls below the wax appearance temperature and wax crystals will precipitate in the crude oil,remarkably increasing the viscosity of crude oil.When the temperature is further lowered to gel point,a wax-like crosslinked network structure is formed.At this time,the waxy crude oil exhibits a gelled state and loses fluidity,directly bringing a lot of mining and pipe transportation difficult.Therefore,improving the low-temperature fluidity of waxy crude oil is of great significance for the safety of pipelines and the reduction of energy consumption.In this paper,the modification characteristics of waxy oils were explored from the aspects of nano pour point depressant and magnetic field treatment.Firstly,the superiority of nano pour point depressant to the modification of waxy crude oil was discussed.The effects of pour point depressants on the wax appearance temperature and morphology of wax crystal were investigated by differential scanning calorimetry and polarized light microscopy.The rheometer method was used to evaluate the modification effect of several pour point depressants from the perspective of viscosity and yield stress.By analyzing the experimental results,it is found that the nano pour point depressant is superior to the traditional pour point depressant in the flow modification of waxy oil.Secondly,the influence of alternating magnetic field on the yield stress of waxy oil was studied.The magnetorheological module of rheometer was used to measure the yield stress of waxy simulated oil and crude oil under various magnetic treatment conditions.The response law of waxy oil to magnetic induction intensity,magnetic field frequency and magnetic treatment temperature was investigated.Experiments show that the alternating magnetic field can significantly change the physical properties of waxy oil and greatly reduce its yield value.Finally,the synergistic effect of the two methods of pour point depressant and alternating magnetic field treatment on waxy oil was further explored.The variation law of yield stess of waxy oil under the action of pour point depressant and alternating magnetic field was obtained.Analysis shows that the combination of the two methods has a better modification effect.