Examination of the Structure and Definition of the Mechanism of Formation of Products by Pyrolysis of Tarim Crude Oil

Pyrolysis of crude oil is an important way to generate natural gas. However, the current analysis pyrolysis gas carbon isotopes and study generation dynamics are not unified, genesis accumulation reservoirs needed conduct in-depth discussions. Therefore, Tarim samples in China were selected perform thermal simulation experiments using autoclave. The hydrocarbon production yield, isotope characteristics gas-generation process Basin studied by GC-MS, FT-IR analysis, respectively. compositions Oilfield determined, including 83.69% content hydrocarbons, 14.08% aromatic compounds, lower than 3% heteroatom compounds. non-monotonic linear relationship C2-5 may be due complexity oil, formation gaseous hydrocarbons can divided into three stages. results showed that δ13C distribution range was −40.5% −10.5%, methane −53.3% −27.4%. lowest value for occurs at 350 °C, corresponding −53.3%. When temperature 250–300 undergoes volatilization preliminary pyrolysis, C4-5 output exceeds 95%. rises 300–500 aliphatic chain begins crack, side branch chains heteroatomic compounds broken, crack form C1-3. Finally, 500–600 C3-5 deeply C1-2, eventually all converted methane.