膏盐岩含量对成熟阶段页岩生烃影响的模拟实验

Simulation Study on the Effect of Gypsum-salt Content on Hydrocarbon Generation in Mature Stage Shale

中国海相和陆相盆地烃源岩层系中均发育厚度不等的膏盐岩层,为探究膏盐岩含量变化对烃源岩生烃过程及产物特征的影响规律,以美国二叠盆地Eagle Ford组页岩为烃源岩,通过添加不同质量分数的天然膏盐岩开展生烃模拟实验,分析滞留于固态反应物中液态产物的特征。结果表明:随着膏盐岩质量分数的增加,海相烃源岩滞留烃产率呈现“先降低再升高”的U型曲线特征,且膏盐岩含量与饱和烃的相对含量呈线性关系,膏盐岩可显著改善原油品质;膏盐岩含量与Pr/Ph、U/R等生物标志化合物参数值正相关,参数应用时需充分考虑膏盐岩含量的影响。研究成果对精确评价页岩油储量潜力、明确页岩油品质变化主控因素具有重要参考作用。

Gypsum-salt rock layers of different thicknesses are developed in the source rock strata of marine and continental basins in China.In order to investigate the influence of the variation of paste rock content on the hydrocarbon generation process and product characteristics of source rocks,taking the shale of Eagle Ford Formation in Permian Basin of the United States as source rock,hydrocarbon generation simulations were made by adding natural gypsum-salt rocks with different mass fractions to analyze the characteristics of the liquid products retained in the solid reactants.The results showed that:with the increase of the mass fraction of gypsum-salt rock,the retained hydrocarbon yield of the marine source rock presented a U-shaped curve of“decreasing then increasing”,and the content of gypsum-salt rock had a linear relationship with the relative content of saturated hydrocarbons,indicating that the gypsum-salt rock could significantly improve the quality of crude oil;the content of gypsum-salt rock was positively correlated with the parameter values of Pr/Ph,U/R and other biomarker compounds,and the influence of gypsum-salt rock content should be fully considered in the application of parameters.The results of the study are important reference for the accurate evaluation of shale oil reserve potential and the identification of the main controlling factors of shale oil quality variation.