Quick Evaluation of Source Rock Kerogen Kinetics Using Hydrocarbon Pyrograms from Regular Rock-Eval Analysis

Source rock kinetics reflects kerogen reactivity that controls the onset and rate of hydrocarbon generation as well as the depth/temperature of oil and gas generation windows. Therefore, understanding source rock kinetics is critical to both quantitative resource modeling and identifying production sweet spots. The study of source rock kinetics requires special laboratory procedure and expertise, the cost of which limits research on specific source rock systems. For quantitative modeling of hydrocarbon generation, kinetic parameters are often adopted from an analogous source rock system available in published data sets or are automatically picked by basin modeling software based on kerogen type or depositional environment and facies. Recent studies (Peters, K. E.; Walters, C. C.; Mankiewicz, P. J. AAPG Bull. 2006, 90, 387-403) revealed that source rock kinetics may vary substantially, even for the same type of kerogen, because of compositional variation. Thus, source-rock-specific kerogen kinetics is more desirable for better characterization of the thermal transformational behavior. On the other hand, the requirements for information regarding the characteristics of source rock reactivity and hydrocarbon generation behavior are time-sensitive for supporting a business decision. Directly assessing reactivity and transformation behavior of source rock based on archived Rock-Eval data would allow for rapid and time-sensitive results to be obtained. This paper proposes a method that characterizes source rock kinetics using pyrograms of archived Rock-Eval analysis. Because the method uses existing Rock-Eval data directly, no new samples and laboratory experiments are required, thus providing a quick and cost-effective technique to determine simple kinetic parameters. The mathematical formulation of this numerical model is described herein, with applications showing the advantage and potential limitations.