Relationships between wetness and maturity of coal-derived gas in China

摘要

Owing to its limited homologous, simple structure, small molecular weight and radius, natural gas could diffuse easily and migrate in a long distance, which greatly increases the difficulties of the study of source rock maturity. So in this paper we study the relationship between natural gas wetness and source rock maturity. Based on 49 coal-derived gas samples from the Ordos, Sichuan, Bohai Bay, Qiongdongnan, Junggar and Turpan–Hami basins in China with integral molecular series, it is discovered that the wetness of natural gas decreases with the maturity (Ro) of source rock. The negative correlation between wetness and maturity was established. Since the wetness could be easily acquired, the Ro could be quickly calculated based on the relationship, which provides important basis for gas source definition and resource evaluation.