Kinetic Characteristics of Kerogens in the Kuonamka Complex, Lower and Middle Cambrian of the Siberian Platform

Abstract

––The kinetic characteristics of kerogen (activation energy and frequency factor distributions of the initial generative potential) determine the dynamics of naphthide generation during catagenesis. In the previous studies on quantitative modeling of naphthidogenesis in the Kuonamka source rocks, the kinetic characteristics were taken by analogy with the known kerogens from other complexes and provinces. It seems relevant to determine the effective kinetic characteristics of the kerogen from the Kuonamka source rocks from experimental data. To estimate the kinetic parameters, specialized multi-rate pyrolysis studies were performed. The variations in pyrolysis data was reported to be presumably associated with the conditions of kerogen and source rock formation during accumulation and diagenesis of organic matter. The effect of carbonate and organic carbon contents on the temperature range of the second pyrolysis peak is recorded. Reconstruction of the average (effective) kinetic characteristics of kerogens from the Kuonamka source rock, was conducted using data on kerogens from Serkinsky-5 and 10 and Tit-Ebya-6 wells, which are less degraded than kerogens from Ust’-Maiskaya-366 well and probably attained the early mesocatagenesis grades. The current average effective kinetic characteristics of kerogen were estimated and corrected for the possible partial degradation of reference samples. The obtained effective kinetic models of kerogen are compared with models of kerogens of various genetic types known from the literature. The estimated effective kinetic characteristics of kerogens or Menil-1 and Type B kerogens with similar characteristics are to be taken, as a first approximation, in regional historical-genetic (basin) modeling of naphthide generation in the Kuonamka source rock.