Theoretical Study of Structural and Spatial Properties of Kerogen

In this study, the structural information and spatial properties of the Longkou kerogen model were obtained by using molecular simulation methods. The density evaluation of the molecular model was carried out to investigate the morphological properties of internal pore structures that are limited or constrained by kerogen density. The density of the lowest-energy kerogen model is 1.01 g/cm3, which is consistent with its experimental value and close to the reference value for Green River Shale kerogen. Radial distribution function analysis indicated that the carbon skeleton of kerogen consists of significant amounts of sp2- and sp3-hybridized carbons. To further investigate the distribution characteristics of internal pore structures and provide valuable insights into the microstructures of the kerogen model, the morphology of pore volumes was created using Connolly surfaces. Meanwhile, a simplified mechanism model of kerogen pyrolysis was proposed based on the Mayer bond order analysis, which provided a strategy to accurately, quickly predict the cleavage behavior in the intrinsic structure of kerogen. This present study reveals inherent chemical features of kerogen and will aid in understanding the microscopic morphology characteristics of the pore network inside kerogen at the molecular level.