Time and Temperature in Petroleum Formation: Application of Lopatin’s Method to Petroleum Exploration

N. V. Lopatin in the Soviet Union has developed a method for taking both time and temperature into account as factors in thermal maturation of kerogen. Lopatin’s time-temperature index of maturity (TTI) values correlate with the thermal regimes corresponding to generation and preservation of hydrocarbons. Because such information is potentially of great interest for oil exploration, a calibration and evaluation have been made of Lopatin’s method. Within the limitations of the data presently available the following statements can be made: The rate of the chemical reactions involved in thermal maturation of organic material appears to double with every 10°C (18°F) rise in temperature. Threshold values of Lopatin’s time-temperature index of maturity (TTI) are: 15Onset of oil generation75Peak oil generation160End oil generation~50040° oil preservation deadline~1,00050° oil preservation deadline~1,500Wet gas preservation deadline>65,000Dry gas preservation deadline TTI values calculated from Lopatin reconstructions consistentlyagree with other maturation parameters commonly used by petroleum geochemists. Potential applications of Lopatin’s method for oil exploration include timing of oil generation, calculation of volume of hydrocarbons generated within a basin, and determination of economic deadlines.