The Constructions and Pyrolysis of 3D Kerogen Macromolecular Models: Experiments and Simulations

Area of Science:

• Geochemistry
• Computational Chemistry
• Chemical Engineering

Background:

• Kerogen, the organic matter in sedimentary rocks, is crucial for understanding hydrocarbon generation.
• Studying kerogen pyrolysis provides insights into the formation of shale oil and gas.
• Accurate molecular models are essential for simulating kerogen pyrolysis.

Purpose of the Study:

• To construct rational macromolecular models of kerogen from deep shales.
• To investigate the effects of temperature and heating rate on kerogen pyrolysis kinetics.
• To simulate kerogen pyrolysis at experimental temperatures and validate the simulation method.

Main Methods:

• Extraction and characterization of kerogens from deep shale samples.
• Construction of 2D and 3D kerogen macromolecular models using physical, chemical, and computational methods (molecular mechanics, global energy minimization).
• Simulation of kerogen pyrolysis using reactive force field (ReaxFF) and hybrid molecular dynamics/force-biased Monte Carlo (MD/fbMC) approaches.

Main Results:

• Reliable 3D macromolecular models of kerogen were established.
• The effects of temperature and heating rate on pyrolysis kinetics were analyzed.
• Simulated gaseous products and residues closely matched experimental results, validating the simulation method.

Conclusions:

• A reliable simulation method for kerogen pyrolysis at experimental temperatures has been developed.
• The study proposes mechanisms for typical kerogen pyrolysis reactions.
• This research aids in understanding the formation pathways of shale oil and gas.