Three sulphur-rich commercial crude oils have been studied,which contain sulphur as high as up to4—12%.These samples were collected from Tertiary hypersaline lake sediments of the Jianghan Basin,Hubei Province at different depths,but above the oil generation threshold(2200m).FPD—GC and GC-MSdata show that aromatic fractions of the crude oils are composed of different homologues of sulphur-containing compounds,including long-chain normal alkyl-thiophenes and-thiolanes,long-chainisoprenoid-thiophenes and-thiolanes,and benzothiophenes.It is worth noting that the distribution patternsof long-chain alkyl-thiophenes and-thiolanes from two shallow-seated crude oils are quite similar to thoseof normal alkanes showing marked even-odd predominance.It seems that the even-odd predominance ofsulphur-containing compounds decreases with increasing burial depth of the crude oils.The majorcomponent of aliphatic fraction is phytane,and similarly the major peaks of aromatic fractions also representC_(20) isoprenoid thiophenes.Some preliminary conclusions have been drawn from the above discussion:(1)Abundant sulphur-containing compounds may be used as an indicator of low mature or immature crude oils produced fromhypersaline lake sediments;(2)Sulphur-containing compounds are considered to be early diageneticproducts of reactions between elemental sulphur or sulfides and alkanes or their precursors(phytols,fattyacids,alcohols,etc.),or of bacterial activities,but not direc■ inputs of organisms. Three sulfur-rich commercial crude oils have been studied, which contain sulfur as high as up to 4-12%. The samples were collected from Tertiary hypersaline lake sediments of the Jianghan Basin, Hubei Province at different depths, but above the oil generation threshold ( 2200m). FPD-GC and GC-MS data show that the aromatic fractions of the crude oils are composed of different homologues of sulfur-containing compounds, including long-chain normal alkyl-thiophenes and-thiolanes, long-chain isoprenoid-thiophenes and-thiolanes, and benzothiophenes. It is worth noting that the distribution patterns of long-chain alkyl-thiophenes and-thiolanes from two shallow-seated crude oils are quite similar to those of normal alkanes showing marked even-odd predominance. It seems that the even-odd predominance ofsulfur -containing compounds decreases with increasing burial depth of the crude oils. major components of aliphatic fractions is phytane, and similarly major the same peaks of around fractions also represent c_ (1) Abundant sulfur-containing compounds may be used as an indicator of low mature or immature crude oils produced from hypersaline lake sediments; (2) Sulphur-containing compounds are considered to be early diagenetic products of reactions between elemental sulfur or sulfides and alkanes or their precursors (phytols, fattyacids, alcohols, etc.), or of bacterial activities, but not direc ■ inputs of organisms.