Sulphur compounds of West Siberian crude oils

The distribution of sulphur compounds in crude oils from levels Yu1, AV6-7, and BV8 of the Samotlor field and in fractions of crude oil of the Sovetsko-Sosninsk field was studied. The proportion of sulphides among the sulphur compounds in the crude oils does not exceed 4%. They include mainly thiacycloalkanes with between 1 and 6 naphthene rings. As the boiling point of the fractions increases, the content of dialkylsulphides decreases, and the proportion of naphthenobenzothiophenes, tetranaphthenothiophenes, dinaphthenobenzothiophenes, and dibenzothiophenes increases. The qualitative and quantitative distributions of sulphur compounds in the crude oils are virtually the same. The total content of sulphur compounds in the crude oils (excluding resinous-asphaltene substances) is about 8 wt.%.