APPROACH TO THE CALCULATIVE FORMULA FOR THE THRESHOLD VALUES OF THE EVOLUTIONARY STAGES OF ORGANIC MATTER

Connan (1974), Hood (1975), Asamhawa (1977), Jiao Shouquan and Zhou Peijun (1982) proposed the formula of the threshold values for the maturation of organic matter based on the relationship between temperature and time.In consideration of the previous works and the fact that the maturity of oil and gas in Sichuan Basin is generally high, eight calculative formulas for the threshold values of source rocks with various types of kerogen are deduced. Taking Upper Permian of Sichuan Basin as an example, the effectiveness of those formulas applied to the dynamic evolutionary process of organic matter in various major tectonic movements in Sichuan Basin is expounded. It is further indicated that for the amount on the timing of the formation of traps with respect to the formation of large amount of oil/gas, the calculative formula is viable and could provide useful in formations.