The conventional understanding of condensate is that almost all condensates derivedfrom sapropelic kerogen are the product of highly matured organic matter(R_0>1.3%) during the late stage of diagenesis or of thermally cracking of high molecularweight hydrocarbons during the early stage of diagenesis. Recent studies indicate thatthe petroleum evaporative fractionation, although to which little attention has been paid, is The conventional understanding of condensate is that almost all condensates derived from sapropelic kerogen are the product of highly matured organic matter (R_0> 1.3%) during the late stage of diagenesis or of thermally cracking of high molecular weight hydrocarbons during the early stage of diagenesis. indicate that the petroleum evaporative fractionation, although to to little attention has been paid, is