"蒙脱石-伊利石"转化过程中矿物的固体酸性和微结构变化及其对催化生烃的影响与机理研究

The role of clay minerals for hydrocarbon generation is a critical problem, yet to be adequately resolved, in the formation theory of oil and gas. So far, the micro-mechanisms of the hydrocarbon generation based on the catalytic reaction on clay mineral still remain unclear, resulting in a bottleneck for the figuring out of the problem. The present proposal starts with the two key mineralogical factors influencing on the hydrocarbon generation, the solid acidity and microstructure of clay minerals, and orient toward the end-member and intermediate minerals of the montmorillonite - illite transformation which is the most characteristic in the hydrocarbon generation. The planning work includes the investigation on the changes of the solid acidity (the types, concentration and strength of the solid acid sites) and microstructure (micro-morphology, interlayer microstructure and porosity) during the mineral phase-transformation and some key medium conditions, and the preparation of the hybrid of clay mineral and some organocompounds, which are selected as the model organics for the simulation of the hydrocarbon-sourced organics. The organocompounds will be located both inside and outside the interlayer region of clay minerals for comparison purpose. The resulting hybrid materials will be used as the starting reactant and placed into a high temperature and pressure reacting system for the experimental studies of the hydrocarbon-generation features as well as the kinetics. The products of both hydrocarbon and solid part will undergo an in-depth analysis, and the relativity between the hydrocarbon-generation and the previously obtained mineralogical-characteristics will be carefully investigated. Based on these mentioned results, the effects and the related mechanisms of the changes of the solid acidity and microstructure during the montmorillonite - illite transformation on the catalytic pyrolysis of the typical groups of the organics will be found out. The fundamental information derived from the currently proposed project is of significance both theoretically and experimentally in providing a key basis for the well understanding of the micro-mechanisms of hydrocarbon-generation caused by the catalytic function of clay minerals.

"粘土矿物对生烃的作用"是油气成因理论中待解的重要科学问题。粘土矿物催化生烃的微观界面作用机制至今不明，是阻碍该问题获得解决的瓶颈。为此，本项目从固体酸性和微结构这两个影响粘土矿物催化生烃的关键矿物学因素入手，以油气形成过程中最典型的"蒙脱石-伊利石"相变之端元和过渡（混层）粘土矿物为研究对象，探索其固体酸性（酸位类型、浓度及强度）和微结构（微形貌、层间微结构和孔结构）在相转化中的变化和机理；并选用合适的模型有机质模拟生烃母质，制备粘土矿物-有机质层外/层间复合物。在此基础上，构建粘土矿物催化有机质的高温高压界面反应体系，以粘土矿物-有机质复合物为反应物，开展生烃实验（含生烃动力学）研究。根据对反应产物的综合分析，及其与粘土矿物性质、结构的对比分析，揭示"蒙脱石-伊利石"转化中固体酸性和微结构变化对有机质特征基团催化分解的影响和机理，为探明粘土矿物催化生烃的微观机制提供理论和实验依据。

“粘土矿物对有机质生烃的作用”是油气成因理论中待解的重要科学问题。粘土矿物催化生烃的微观界面作用机制至今不明，是阻碍该问题获得解决的瓶颈。为此，本项目从粘土矿物的固体酸性和微结构等矿物学因素入手，以油气形成过程中最典型的“蒙脱石—伊利石”相变之端元和过渡（混层）粘土矿物为研究对象，探索其固体酸性（酸位类型、浓度及强度）和微结构（微形貌、层间微结构和孔结构）在相转化中的变化和机理；并选用合适的模型有机质模拟生烃母质，制备粘土矿物-有机质层外/层间复合物。在此基础上，构建粘土矿物催化有机质的高温高压界面反应体系，以粘土矿物-有机质复合体为反应物，开展高温压生烃实验研究。研究结果发现，粘土矿物的固体酸性和微结构变化对有机质特征基团催化分解具有重要的影响。粘土矿物的B酸位通过促使有机质以阳碳离子方式发生热解，气态烃产率增加，异构化程度增强。以脂肪酸类有机质为例，伊蒙混层（累托石）对有机质的热解表现出更大的催化活性，蒙脱石次之，最后是伊利石。粘土矿物对某些有机质的热解还表现出抑制热解的效应，这与有机质的性质有很大关系。对于膨胀性的粘土矿物（如蒙脱石），其层间域结构对某些有机质的热解起到了层间放大的作用，由于其层间域中具有丰富的较强的B酸位可促使层间有机质产生大量的气态烃。还能由于其空间位阻的影响对某些有机质起到更大抑制热解作用。上述研究结果表明，粘土矿物催化有机质热解的过程与结果与粘土矿物类型、界面反应发生位置（粘土矿物层间或层外）、有机质性质以及反应环境（开放体系或封闭体系）密切相关。地层中粘土矿物的微结构及固体酸性（酸量、酸强度和酸类型）、有机质性质以及粘土矿物与有机质的结合方式对有机质的生烃产生明显的影响，这些因素在评估烃源岩的生烃潜力和生烃机理时不容忽视。