不同类型烃源岩排烃模式对比及差异性探究

Comparison and exploration of hydrocarbon expulsion patterns of different types of source rocks

烃源岩的排烃是准确预测含油气盆地油气资源必须涉及的一个非常重要的环节,为了得到不同有机质类型烃源岩的排烃效率、排烃机理,选取不同有机质类型烃源岩进行了黄金管模拟实验,总结了不同类型烃源岩在各演化阶段产物的变化特征与排烃效率。结果表明,烃源岩类型对总生成油与残留油中轻重烃的比例影响较大,但是对排出油中轻重烃的比例影响较低,排出油中均表现为在未熟—成熟阶段以重烃为主,在高熟—过熟阶段以轻烃为主。烃源岩的类型对生排油量的影响明显,烃源岩的类型越好,生排油量越高。Ⅰ型烃源岩的生排油量最高,Ⅲ型烃源岩最低。烃源岩类型越好,排油效率越高。Ⅲ型烃源岩排油效率低,与其生成气态烃较多、显微组分中镜质组含量较高有关。

Hydrocarbon expulsion from source rocks is a very important part in the accurate prediction of oil and gas resources in petroliferous basins.In order to obtain the hydrocarbon expulsion efficiency and mechanism,the source rocks of different organic matter types were selected for the gold tube simulation experiments,product change characteristics and hydrocarbon expulsion efficiency of different types of source rocks in different evolution stages are summarized.The results show that,the type has a great influence on the proportion of light and heavy hydrocarbons in total oil and residual oil,but has little on that in discharged oil;the discharged oil is dominated by heavy hydrocarbons in the immature-mature stage and light hydrocarbons in the high-mature-overmature stage.The type has obvious influence on the amount of oil generation and discharge.The better the type of source rock is,the higher the amount of oil generation and discharge is.The oil generation and discharge amount of typeⅠsource rocks is the highest and that of typeⅢsource rocks is the lowest.The better the type of source rock is,the higher the oil discharge efficiency is.The low oil discharge efficiency of typeⅢsource rocks is related to the high generation of gaseous hydrocarbon and the high content of vitrinite in macerals.