烃源岩催化酯生烃动力学研究——以东营凹陷沙河街组三、四段烃源岩为例

烃源岩生烃动力学广泛应用于含油气盆地烃源岩评价与勘探中。为模拟低成熟烃源岩的实际沉积环境,实验选取了抽提有机质后的东营凹陷下第三系沙河街组三、四段烃源岩为矿物催化剂,以十八烷酸甲酯为模型化合物,在高压下做矿物低温催化脂肪酸酯脱羧生烃动力学实验。求取了化学反应的动力学参数,并分析了烃源岩层段的pH值与Eh值。结果表明,矿物对脂肪酸酯的脱羧生烃具有明显的催化作用,用连串反应模型处理脂肪酸酯的水解反应基本上为一级反应,而生烃反应则基本上为零级反应。认为对于同一类型的烃源岩,其所处的氧化还原环境对有机质的生烃有较大的影响;而对于不同的烃源岩,矿物的组成则起着非常重要的作用。

Kinetics of Hydrocarbon Generation of Fatty Acid Ester Catalyzed by Source Rock: A Case of Oligocene Sahejie Source Rocks in Dongying Depression,Bohaiwan Basin

Kinetics of Hydrocarbon Generation is widely applied in source rock evaluation. The samples of immature source rock that are collected from Oligocene Sahejie Formation Member-3 and Member-4 in Dongying Depression Basin are chosen for test and analysis. To simulate real sedimentary environment of source rocks and obtain kinetic parameters, the samples of source rocks that had been extracted with organic solvents were chosen as catalyst and methyl stearate was chosen as model compound. In addition, pH and Eh values of the source rocks were analyzed. The results indicate that the hydrocarbon generation of fatty acid ester can be catalyzed obviously by minerals and the reaction can be treated as consecutive kinetic model. The hydrolysis reaction is a first-order reaction and the hydrocarbon generation reaction is a zero-order reaction. Redox environment has a significant influence on the hydrocarbon generation of organic matter catalyzed by the same kind of source rocks. Component of minerals has an important effect on hydrocarbon generation catalyzed by different minerals.