摘要
Isotope composition analysis is an important technique in researches on oil-gas-sourcecorrelation and evolution of sedimentary organic matter. Many δ<sup>13</sup>C<sub>1</sub>-Ro relationship mod-els for natural gas have been suggested, and almost all of them indicate that naturalgas derived from the type-Ⅲ kerogen is isotopically heavier than that from the type-Ⅰ
