Synthesis And Performance Evaluation Of Oil-soluble Nanocomposite Viscosity Reducer

With the continuous exploitation of conventional oil and gas resources,the potential of heavy oil is constantly highlighted.However,heavy oil has the disadvantages of high density,high viscosity and difficult production and transportation.Combining the advantages of nanomaterials with the characteristics of oil-soluble viscosity reducers,the research and development of oil-soluble nanocomposite viscosity reducers with excellent performance is a new idea to solve the problems of low heavy oil recovery and difficult pipeline transportation.In this paper,the basic physical properties of Liaohe heavy oil are analyzed,and the four-component molecular structure of heavy oil is determined,and the heavy oil model is constructed by combining the improved B-L method.Then,the monomers suitable for viscosity reduction of Liaohe heavy oil were screened by molecular simulation,and the feasibility of synthesis of oil-soluble viscosity reducer was simulated according to the results of molecular simulation.Oil-soluble viscosity reducer was synthesized by solution polymerization of stearyl methacrylate,styrene and maleimide.The effects of monomer ratio,reaction temperature,reaction time and initiator addition on the viscosity reduction of heavy oil were investigated.The results showed that when the monomer ratio was(octadecyl methacrylate,styrene,maleimide)10:8:3,the optimum reaction conditions were:reaction temperature 70°C,reaction time 6h,initiator addition amount1wt%.The oil-soluble viscosity reducer prepared under this experimental condition has the best viscosity reduction effect when the addition amount is 0.3wt%,and the viscosity reduction rate is 55.49%.The characterization results of infrared and hydrogen spectrum showed that the oil-soluble viscosity reducer was successfully synthesized.At the same time,the oil-soluble viscosity reducer has good thermal stability and dispersibility.Graphene oxide composite viscosity reducer(SSM-GO)with different carbon contents was prepared by solvothermal method using graphene oxide and oil-soluble viscosity reducer as raw materials.The oxidized carbon nanotubes were prepared by hydrogen peroxide oxidation method.The oxidized carbon nanotubes composite viscosity reducer(SSM-OCNT)with different carbon content was prepared by solvothermal method using oxidized carbon nanotubes and oil-soluble viscosity reducer as raw materials.The structure and microstructure of the viscosity reducer were characterized by SEM,FTIR and XRD.The results showed that the two nanocomposite viscosity reducers were successfully prepared.The optical microscope(OM)test results showed that the two nanocomposite viscosity reducers had good dispersibility.Based on the comprehensive structural performance characterization and effect evaluation,the viscosity reduction rates of SSM-1wt% GO and SSM-1wt% OCNT were 56.93% and 64.12% at 50°C,respectively.The order of viscosity reduction effect of each viscosity reducer is as follows:oxidized carbon nanotube composite viscosity reducer,oxidized graphene composite viscosity reducer and oil soluble viscosity reducer.The above results show that the oil soluble viscosity reducer plays a role of hydrogen bond,solvation layer and dissolution dispersion,which destroys the colloidal asphaltene stacking structure of heavy oil and reduces the viscosity of heavy oil.Nano-composite viscosity reducer can combine the advantages of traditional oil-soluble viscosity reducer with the advantages of carbon nanomaterials.Nano-type viscosity reducer can penetrate into colloidal asphaltene and fully contact with heavy oil by virtue of its small particle size,large specific surface area and good dispersion performance.Due to the excellent nano-characteristics of carbon nanotubes,the effect of oxidized carbon nanotubes composite viscosity reducer is better than that of graphene oxide composite viscosity reducer and oil-soluble viscosity reducer.