The suifonated asphait is one of the indispensable preparations in the modem drilling engineering at home and abroad as an additive in drilling fluid with high performance and multifiunetion.The sulfonated asphalt for additive in drilling fluids is prepared by sulfonation reaction,using straight asphalt, desolventizing asphalt and oxidized asphait as raw materials.In this dissertation,the reaction wctivity of four constituents of asphalt including saturates,aromatios,resin and asphalene in presence of hexane as solvent is studied.The confuence of asphalt composition on physicochemical properties of product and relations between composition of asphalt and application performance of the produet are discussed.The optimal processing condition of preparing sulfonated asphalt is detemined.The researching results indicate that the perfomance of sulfonated asphalt is mainly determined by the chemical compositions of the material asphalt and sulfonating technological conditions. The sequenp of sulfonation reaction activity of the four constituents in the material asphalt shows as follows:
resin>aromaticssaturate > asphaltene.The optimal composition of raw
materials should be as follows:asphaltene :5%,resin ≥ 35%,
aromatics 230%,saturate S 15%,and aromatic + resin ≥75%,
