The Synthesis And Reaserches Of Oil-soluble Viscosity Reducers For Gudong Heavy Crude Oil Of Shengli Oilfield

With rich and vast heavy crude oil resources in China,it is imperative to develope and utilize domestic heavy crude oil resources for energy security and national interests.However,the viscosity characteristics of heavy crude oil seriously hamper its normal exploitation and utilization.Oil-soluble viscosity reducers for heavy crude oil are being widely studied because of its many advantages such as processing convenient,saving light oil consumption,low cost and avoiding dehydration of emulsified heavy crude oil.But,poor viscosity reducing capabilityand limited applicability for heavy crude oils restrict the study and application of oil-soluble viscosity reducers.In this paper,some physical and chemical properties of K92 heavy crude oil in Shengli Oilfield were measured and analyzed.Then,one oil-soluble tetramer viscosity reducer(ASMZ)was synthetized for viscosity reduction of K92 heavy crude oil with high amount of asphaltene and resin.The best synthesis condition was determined: ratio of monomers(Acrylate,Styrene,Maleic anhydride,Acrylamide)8.5:6:4:0.6,reaction temperature 85 ?,reaction time 6 h,amount of initiator 1.4%.At the using temperature of 50 ?,viscosity reduction rate could reach to 48.49% using 500 ?g/g ASMZ.Molecular weight and distribution of ASMZ were analyzed using GPC,illustrating Mw 2~3million,Mn 1~2million and polydispersity index about 2.Besides,the effect of polymer intrinsic viscosity on viscosity reduction capability of ASMZ for heavy crude oil was studied.Then from the experimental results it was founded that with the polymer intrinsic viscosity of about 30~40 mL.g-1,ASMZ showed the best viscosity reduction result.Moreover,some surfactants such as SDS,NP-7 and CTAB were mixed with ASMZ,contriving to improve viscosity reducing ability,and the effect on viscosity reduction of surfactant species and amount were studied.At 50 ?,viscosity reduction rate could reach to 68.59% using 500 ?g/g ASMZ mixed with 0.7%SDS.At last,in this paper,viscosity reducing mechanism of ASMZ mixed with surfactants SDS,NP-7 or CTAB was studied in the standpoints of asphaltene association properties and colloidal stability of heavy oil by methods of relative viscosity and mass fraction normalized conductivity.And,effects of viscosity reducers on asphaltene were analyzed by Infrared Spectroscopy.Then,based on these experiments results,viscosity reducing mechanism was explained in this paper.