东营凹陷民丰地区天然气生成机理与化学动力学研究

Kinetics of Gas from the Pyrolysis of Source Rock and Oil Cracking and Its Application in the Genesis of Natural Gases in Minfeng Area of Dongying Sag

民丰地区天然气存在源岩热解和原油裂解成因的争议。本文采用高压釜封闭体系对该区烃源岩和原油样品分别进行了热模拟实验，从烃类气体生成过程、气态烃与部分单体烃生成动力学特征讨论了二者的生气机理，认为原油裂解比源岩热解生气活化能高30～40kJ／mol，原油比源岩生气需要更高的热力学条件。模拟实验证实，成熟阶段源岩热解气与原油裂解气相比，以环烷烃和芳烃相对含量低为特征，与民丰地区产出的天然气组成更接近，据此认为该区天然气主要为源岩热解成因。

It is controversial about the origin of the natural gas in Minfeng area. By using thermal simulation experiment of the sealed system, the genetic mechanism of Eocene source rocks and oils are discussed in the generation process of hydrocarbon, the generation kinetics of the gas and some individual hydrocarbon. The result shows that the activation value of oil cracking is 30 kJ/mol higher than the thermolysis of source rocks. At the mature phase, the cracking gas from source rock contains less aromatic hydrocarbons and cycloparaffinic hydrocarbons. In view of above, natural gases in Minfeng area is mainly from Eocene source rocks.