Theoretical Investigation of Geochemical Processes

近年来，越来越明显的是，了解沉积盆地中有机/无机界面以及细菌和粘土矿物的地球生物化学作用，对于建立准确、全面的成岩过程平衡和质量传递模型至关重要。在这些过程中发生了无数的可逆和不可逆反应，所有这些反应原则上都符合热力学分析。例如，热力学计算可以与成分数据结合使用，以确定成岩系统中的稳定和亚稳定平衡状态，并评估对反应进程的动力学约束。这类计算可以借助这个实验室在过去几十年中发展起来的状态方程来进行。这些方程使得研究在高温和压力下各种矿物、气体和水物种之间的反应的化学和热力学后果成为可能。这项建议的目的是请求在成岩作用过程中继续进行这项研究的长期支助，重点是有机/无机反应和具有地球生物化学意义的反应。该项目未来五年的目标包括：全面计算有机液体、固体、气体和水的热力学性质随温度和压力的变化，调查石油中的有机分子、油田卤水中的水的亚稳平衡的程度，以及油气藏和源岩中的自生矿物组合。在高温和高压条件下，对细菌在成岩过程中作用的热力学约束进行了量化，并计算了沉积盆地中涉及有机/无机反应和粘土矿物的传质。

It has become increasingly apparent in recent years that understanding the organic/inorganic interface and the geobiochemical role of bacteria and clay minerals in sedimentary basins is crucial to development of accurate, comprehensive models of equilibrium and mass transfer in diagenetic processes. A myriad of reversible and irreversible reactions occur in these processes, all of which are in principle amenable to thermodynamic analysis. For example, thermodynamic calculations can be used together with compositional data to identify stable and metastable equilibrium states in diagenetic systems and assess kinetic constraints on reaction progress. Calculations of this kind can be carried out with the aid of equations of state developed in this laboratory over the past several decades. These equations make it possible to investigate the chemical and thermodynamic consequences of reactions among a wide variety of minerals, gases and aqueous species at elevated temperatures and pressures. The purpose of this proposal is to request long-range support for continuation of this research in the context of diagenetic processes with emphasis on organic/inorganic reactions and those of geobiochemical interest. The goals of the project over the next five years include comprehensive calculation of the thermodynamic properties of organic liquids, solids, gases and aqueous species as a function of temperature and pressure, investigation of the extent to which metastable equilibrium prevails among organic molecules in petroleum, aqueous species in oil field brines, and authigenic mineral assemblages in hydrocarbon reservoirs and source rocks, quantification of thermodynamic constraints on the role of bacteria in diagenetic processes at elevated temperatures and pressures, and calculation of mass transfer involving organic/inorganic reactions and clay minerals in sedimentary basins.