Extrapolation of the kinetics of oil and gas formation from laboratory experiments to sedimentary basins

Abstract

It is generally accepted that the formation of oil and gas from sedimentary organic matter—or kerogen—is adequately described by kinetic models based on first-order kinetics with rate constants obeying an Arrhenius equation. These models, which are extensively used in oil exploration to assess the petroleum potential of sedimentary basins, are based on geological observations^1,2,3,4,5,6, but are formally quite similar to models designed to simulate oil-shale pyrolysis^7,8,9 or coal processing^10,11,12. The idea of blending these two approaches is not new (see, for example, ref. 2), but until now the most sophisticated attempts reproduced only the gross features of kerogen cracking on a geological timescale⁵ or were uncontrolled by geochemical measurements^13,14. Here we show that the kinetic parameters determined from the laboratory pyrolysis of an immature kerogen sample apply to the conditions of sedimentary basins, altough the time and temperature scale are completely different.