Terahertz Spectral Characterization Of Kerogen Thermal Evolution

Oil and natural gas are important energy and chemical raw materials,and kerogen is the raw material of hydrocarbon source rock.The molecular structure and evolution of kerogen are of great significance for guiding exploration and development.In this paper,the terahertz time-domain spectroscopy system is used to characterize the evolution of marine,terrestrial and Huadian oil shale kerogen.This study provides a reference value for the in-depth study of the evolutionary hydrocarbon generation mechanism of source rocks in petroleum geology and the determination of kerogen oil and gas generation points.The main contents and conclusions of this paper are as follows:(1)In this paper,the kerogen samples were characterized by terahertz time-domain spectroscopy,and the terahertz time domain information of the samples was obtained.According to different maturity(experienced by different temperature and pressure)variation characteristics values of the kerogen terahertz absorption,refraction and dielectric constant established an evolution model of kerogen with different properties.(2)Based on the theory of computational chemistry.The Gaussian software was used to model the molecular structure,structure optimization and frequency calculation of the kerogen functional group.The mode of motion of the molecules was analyzed by Gauss View video function,identifying weak vibrations and large skeleton vibrations of different functional groups at different frequencies.(3)The kerogen at different temperatures was characterized by Raman spectroscopy.The changes of D peak and G peak,and the analysis of peak position difference and peak ratio were used to characterize the maturity of kerogen.