Synthesis Of Amphiphilic Polymers Containing Siloxane Quaternary Ammonium Salt And Application On Reducing Viscosity Of Heavy Oil

The synthesis of viscosity agents and mechanism of viscosity reduction become a research hotspot with the deepening of heavy oil exploration degree.The existing viscosity reducers have some limitations,especially poor demulsifecating/dehydrating capacity,making post-processing cost high.Ideally,the reducer should have high viscosity reducing efficiency,great heat and salt resistance,and especially the coarse emulsion has the characteristics of reducing viscosity when flowing and layering after standing.The macromolecule reducer possesses more application prospects taking both advantage of surfactants and polyacrylamides.In this paper,a siloxane quaternary ammonium salt(SQ)was synthesized and characterized.Three kinds of copolymers were synthesized via solution polymerization and molecular composition was characterized.This paper also made a systematic evaluation on the solution and viscosity reduction properties.The main work and results of study are as follows:1,A novel siloxane quaternary ammonium salt(SQ)was synthesized and characterized by 1H-NMR and FI-IR.The behavior of monomer in aqueous solution was studied by surface tension,electrical conductivity and fluorescence spectroscopy technique.The results indicated the monomer showed a satisfactory surface activity in aqueous solution and the surface tension of solution could be reduced to 30 mN/m when the critical micelle concentration(CMC)is 0.76 g/L.2,Three kinds of copolymers were synthesized via solution polymerization of SQ with acrylamide(AM)and 2-acrylamide-2-methylpropanesulfonate acid(AMPS).Molecular composition was characterized by 1H-NMR,FI-IR spectroscopy and element analysis.The molecular weight of copolymers was detected by means of static laser light scattering.The thermogravimetric analysis of copolymers samples showed a satisfactory thermal stability,and it possessed an application prospect.3,The performance of polymer solution was studied by surface tension,interfacial tension,fluorescence spectroscopy,dynamic light scattering and apparent viscosity test,and effects of the concentration and temperature on the aggregation behavior of polymer in aqueous solution were examined.Results showed that,comparing with the monomer,the surface activity of copolymers was poorer,while interface activity was high;The addition of siloxane monomer enhanced the wettability of polymer solution to heavy oil.4,The copolymers were assessed by measuring their performance as viscosity reducer,and the effect of oil-water ratio and the polymer concentration on viscosity reduction efficiency was studied.The results showed that with the decrease of the oil/water ratio and increase of polymer concentration,the viscosity of the emulsion would be stable after rapidly decline in first.According to the results,the optimal water-oil ratio and polymer concentration were selected.the stability of the emulsion was studied via the observation of emulsion type and stability analysis,and the resistance to salt and anti-aging performance of polymer viscosity agent containing silicon were studied.And results showed this type of oil reducers had excellent comprehensive performance,such as high viscosity reducing efficiency,great heat and salt resistance,but above all the demulsification/dehydration effect well solved the problem of post-processing.The viscosity reduction rate of PASQ and PAASQ exceed 90%when the concentration is 1.0g/L;the resistance capacity of sodium chloride,calcium chloride and magnesium chloride respectively are 15000mg/L,800mg/L and 800mg/L;the reduction effect remains the same after ageing for 15 days at 65?;most important of all,polymer agents with siloxane quaternary salt can reduce the stability of the emulsion.In this article,we adopt optical analysis method to measure the dehydration of emulsion in less than half an hour,and the results showed that after adding PAASQ the dehydration rate of emulsion could reach to 90%.Viscosity agents containing siloxane have a unique characteristics of reducing viscosity when flowing and layering after standing.