Coordinated Theoretical and Analytical Investigations of Organic Transformations During Diagenesis and Hydrothermal Alteration

9418500冲击 尽管已经进行了大量的研究来表征地质流体的有机组成，但对于在自然过程中热水溶液与有机物质相互作用时发生转化的基本反应途径和机制仍然只有初步的了解。 新兴的亚稳平衡范式提供了一个框架，通过这个框架，地质流体（如油田卤水和热液溶液）中有机化合物之间的动态关系使人们更清楚地了解导致这些流体观察到的组成的有机转化，并产生了关于石油起源、运输、积累和蚀变的新想法。 该研究旨在扩大我们对亚稳态平衡态的认识，并提高其对地球化学过程的适用性。 在拟议的研究中要解决的具体问题包括：亚稳平衡态的宽度。 目前，介稳平衡的论点主要是基于油田卤水中的羧酸。 存在于自然溶液中的其他哪些有机化合物参与亚稳态平衡状态，哪些不参与？ 是否有特定的化合物家族能达到亚稳态平衡，而其他的却不能？ 亚稳态平衡态的机械学意义。 观察到的亚稳态平衡关系是否可以用来解释自然环境中实际发生的反应途径？ 需要催化剂。 推断的途径是否需要催化剂的参与？ 在这些环境中有哪些催化剂，从哪里来？ 微生物在多大程度上催化这些反应？ 这些问题将通过一种方法来解决，该方法将理论计算与自然和实验溶液中有机溶质的采样和分析相协调。 这一努力将包括：1）地质流体的采集和分析（最初是油田盐水）以获得比目前可用的更彻底的有机组成的清单，2）将这些分析结合到亚稳平衡的新测试中，这将允许我们识别哪些化合物参与亚稳平衡，3）使用这些计算的结果，确定有机化合物在自然环境中转化的途径，4）将这些结果与实验室研究进行比较，以确定哪些反应途径需要催化，以及5）开始寻找可能的催化剂。

9418500 Shock Despite the enormous amount of research that has gone into characterizing the organic composition of geologic fluids, there still remains only a rudimentary understanding of the fundamental reaction pathways and mechanisms by which transformation occur when hot aqueous solutions interact with organic matter in natural processes. The emerging paradigm of metastable equilibrium provides a framework with which the dynamic relationships among organic compounds in geologic fluids such as oilfield brines and hydrothermal solutions is leading to a clearer understanding of the organic transformations responsible for the observed composition of these fluids, and has lead to new ideas about the origin, transport, accumulation and alteration of petroleum. The proposed research seeks to expand our knowledge of metastable equilibrium states, and improve their applicability for understanding geochemical processes. Specific issues to be addressed in the proposed research include: The breadth of metastable equilibrium states. At present, metastable equilibrium arguments are based largely on carboxylic acids in oilfield brines. Which other organic compounds present in natural solutions participate in metastable equilibrium states, and which do not? Do specific families of compounds reach metastable equilibrium, while others do not? The mechanistic implications of metastable equilibrium states. Can the observed metastable equilibrium relationships be used to construe the reaction pathways that actually occur in natural settings? The need for catalysts. Do the inferred pathways require the participation of a catalyst? What catalysts are available in these environments and in what from? To what extent do microorganisms catalyze these reactions? These issues are to be addressed through an approach that coordinates theoretical calculations with sampling and analysis of organic solutes in natural and experimental solutions. This effort will include: 1) collection and analysis of geologic fluids (initially oil-field brines) to achieve a more thorough inventory of their organic composition than is presently available, 2) incorporating these analyses into new tests of metastable equilibrium which will allow us to identify which compounds participate in metastable equilibria, 3) using the results of these calculations, identify the pathways by which organic compounds are transformed in natural settings, 4) comparison of these results with laboratory studies to identify which reaction pathways require catalysis, and 5) initiating the search for likely catalysts.