Oil generation kinetics determined by fluorescence response of oil-prone kerogens during DAC pyrolysis

Abstract

The fluorescence spectra of kerogens isolated from thirteen oil-prone source rocks of different depositional environments were measured in situ during pyrolysis in a diamond anvil cell at five heating rates (1, 3, 8, 25, and 50 ºC/min) up to 600ºC. The successive increase in temperatures of the brightening with increasing heating rate suggests a kinetic control of the fluorescence response resulted from fluorescing liquid petroleum generation. The Ea distribution for each kerogen falls within a narrow range (＜ 2 kcal), implying that the liquid petroleum generation for an individual oil-prone source rock may take place in a narrow maturity range (i.e. small oil window). The calculated kinetic parameters of these kerogens, Ea (46 to 75 kcal/mol) and log Ao, show a linear cross-correlation suggesting that the reaction measured by fluorescence corresponds approximately to the kerogen-to-liquid transformation. This technique has the potential to isolate the timing of liquid petroleum formation from bitumen or gas generation.