Research And And Evaluation Of Polymer Heavy Oil Viscosity Reducer

This paper has analyzed the application of heavy oil viscosity reduction method in heavy oil reservoirs,the mechanism of chemical viscosity reduction method and the direction of development,aiming at deficiencies of the oil soluble and water soluble polymer emulsifier,combined with the characteristics of heavy oil samples,then,my work is to design and improve a series of products which include three kinds of oil soluble polymer viscosity reducer:double long chain ester-styrene-vinyl acetate polymer(DMSS),double long chain amine-styrene-vinyl acetate polymer(DASS),amphiphilic monomers-acrylic-eighteen ester styrene-vinyl acetate polymer(AOSV)and a water soluble polymer emulsifier:ethylene glycol methyl ether-acrylate acrylamide-alkyl hydrophobic monomer polymer(PMAH).These products were characterized by the corresponding FTIR,NMR and thermogravimetry.Tahe crude oil and Shengli crude oil as samples in 0.8wt%oil soluble viscosity reducer and 50?,and net viscosity of DMSS after optimizing the ratio of rate can reach 55.8%,slightly better than that of the conventional SMA polymer,which shows that the oil soluble polymer double long chain alkyl plays an important role,can provide more attachment points in the three-dimensional network structure,reduce the release of wax crystals,ensure the ductility and space,as a shield to periphery of the asphaltene aggregate into a nonpolar environment.In addition,the alkyl chain length(C12-C18)showed that the long chain more advantages than short chain viscosity on viscosity reduction effect.The performance of AOSV introduced appropriate amphiphilic monomers increases significantly,and the net viscosity reduction rate can reach 71.4%,which showed that amphiphilic molecules with good dispersion and interfacial activity,promote the interaction between the molecules and polymer molecules in heavy oil.In the study of structure-activity relationship,the oil soluble polymer molecular weight also plays a vital role,and it show a downward trend of the viscosity when the molecular weight(Mw)of oil soluble polymer more than 2000Da,which can be explained that control of smaller molecular weight is good for viscosity reduction effect.In the ratio of oil to water 7:3 and conventional 3300-45000mg/L salinity,emulsion viscosity reduction of the 0.08wt%water soluble polymer emulsifier(PMAH)more than 98%.The emulsifying effect is obvious by ion suppression of minerals when salinity more than 100178mg/L.In the temperature test,the viscosity reduction rate of polymer emulsifier decreased by 3%and maintained over 95%after 180? and 24h.The molecular structure has not damaged under high temperature,and still has had good emulsification.The molecular simulation study of oil soluble polymer viscosity reducer has introduced by using Materials Studio software,calculated the density change and energy change before and after the reorganization of heavy oil.The density of system with 1.06 g/cm3 has decreased,and the minimum can be about 1.01 g/cm3;the potential energy of the system has reduced and the non-bond energy cain significantly negative growth,which confirms that heavy oil molecules and polymer interactions form a new uniform structure system to reduce viscosity of heavy oil.In the mechanism of emulsion stability,heavy oil emulsion composition and size uniformity factor analysis confirmed that the asphalt and resin are beneficial to the stability of the emulsion.The effect of the content of the specific heavy oil on the emulsification of heavy oil needs to be studied in practice.The proper concentration can improve the emulsion size and distribution,the distribution of small and close extremely emulsion is beneficial to the emulsion stability by optical microscope analysis.