Research On A Viscosity Reducer For Oil-soluble Heavy Oil Containing Hydroxyl Type

Heavy crude oil is gaining attention from various countries because of the increasing oil demand and the decreasing production of conventional oils.Conventional technology is difficult to adapt to exploit the heavy oil with poor liquidity and relative density,which seriously hinders China's abundant oil exploration.There are the vital significance and economic value for solving problems in exploitation and transportation by development of efficient viscosity reducer.In this paper,the oil-soluble viscosity reducer technology is utilized due to its exceptional performance by analyzing the advantages and disadvantages of the several commonly viscosity reduction techniques for heavy oil.The formation of crude oil varies greatly depending on the geological structure,so it is necessary to analyze the basic physical properties of crude oil.In this paper,the viscosity reduction effect of the heavy oil is obvious when the temperature reaches 50aC by exploring on the heat sensitivity,and the viscosity of the heavy oil is 25100 mPa·s.According to the relevant industry standards,the basic physical properties of the heavy oil were respectively analyzed,such as the water content,density and element content of crude oil.And emphasize the extraction and measurement of the four components of the heavy oil,these above results can be concluded that the heavy oil has the characteristics of low water content,high density and high viscosity,and belongs to the extra heavy oil with a high content of heavy components.The viscosity of heavy oil has a close relationship with the content of heavy components contained in it.Therefore,in this paper,two oil-soluble viscosity reducers with different polar groups were designed aiming to this extra heavy oil with high content of heavy components.And the synthesis conditions of them were optimized by single factor experiment,the results indicated that the synthesis conditions of them were similar,where the monomer ratio was 3:5:2,the reaction temperature was 70?,the reaction time was 6h,and the initiator addition amount was 1.2%.The viscosity reduction ratios after the optimized the viscosity reducers(FI-1,FI-2)were 50.82%and 56.0%,respectively.The optimized viscosity reduction performance of the two viscosity reducers at different temperatures was evaluated,the results indicated that the viscosity reduction effect of the viscosity reducer FI-2 was better than FI-1 at the same temperature.In order to further explore the reasons for the different viscosity reduction effects of the two viscosity reducers on heavy oil,the structure of the resin were firstly studied by elemental analysis,GPC,and infrared,indicating that the content of heteroatoms in the resin is high,and these heteroatoms exist in the form of polar functional groups in the resin molecules,which leaded to the aggregation of resin molecules in heavy oil.Then,the results of UV-visible spectrophotometer showed that the viscosity reducer FI-2 had the better inhibition of aggregation on the resin aggregate than FI-1,and the result of the stronger dispersion of resin aggregates for FI-2 was further confirmed by scanning electron microscopy.Similarly,the structure of asphaltenes in heavy oil was explored by elemental analysis,GPC,infrared and nuclear magnetic resonance spectroscopy,and the approximate structure of asphaltene average molecular was proposed.Combined with the results of infrared and energy simulation,it was shown that can form the stronger hydrogen bond interaction between the the viscosity reducer FI-2 and asphaltene molecules than FI-1,and further analysis by X-ray diffraction and scanning electron microscopy demonstrated that the viscosity reducer can disperse the asphaltene aggregates by hydrogen bonding with asphaltenes leading to the change its original dense structure.Finally,it was also confirmed by the determination of the component content after the addition of the viscosity reducing agentes to the heavy oil that the viscosity reduceres also disperse the heavy components in the heavy oil system.In summary,the reason why the two oil-soluble viscosity reducers have different viscosity reducing effects on the heavy oil is explained.