Hybrid modeling in porous media

PI建议使用各种技术来模拟与地下甲烷演化相关的多孔介质中的过程。PI将结合联合收割机传统的连续偏微分方程（PDE）为基础的模型在中尺度，即实验室或现场规模，连续和离散模型在孔隙尺度。 特别是，粗粒度的统计力学模型被用来开发更好的表征亚稳态现象，如吸附和相变。不同的模型将被连接起来，并尽可能根据需要动态地交换数据。连续介质模型的挑战在于其非线性耦合特性和处理热力学约束，而孔隙尺度和离散模型的困难在于其巨大的计算复杂性。在本项目中，项目团队应制定方法，通过确保微尺度结果在概率意义上具有意义，将其封装为连续体模型可用的"库条目"形式。该项目包括计算研究，算法开发，模型和相关误差的严格分析。该调查将集中在全球气候和能源研究的两个重要应用，即增强煤层气（ECBM）回收和模拟海底沉积物（MH）中的甲烷水合物演化。需要为这些应用建立新的计算模型及其数学分析，以便更好地了解各种相关危害，并改进对甲烷命运及其管理的预测。该项目的主要影响是在地下模型之间的建模新范式的发展，并在孔隙尺度现象如何影响中尺度过程的更好的理解。项目成果将直接或间接地帮助地下水文、油气储层建模和地质碳储存项目的建模工作。此外，各种其他学科将受益于新的混合离散-连续算法在这个项目中开发。其他社区福利包括研究人员建立的孔隙尺度基准项目，研究生和本科生的跨学科培训，以及新的高级/研究生级别课程和研讨会的开发，致力于与全球能源和气候问题相关的过程建模。

The PI proposes to use a variety of techniques for modeling processes in porous media relevant to modeling methane evolution in subsurface. The PI will combine traditional continuum partial differential equations (PDE)-based models at mesoscale, i.e. lab or field scale, with continuum and discrete models at porescale. In particular, coarse-grained statistical mechanics models are used to develop better characterization of metastable phenomena such as adsorption and phase transitions. The different models will be connected and, to the extent possible, will exchange data dynamically and on demand. The challenges to continuum models are in their nonlinear coupled character and handling thermodynamics constraints, while the difficulties to the porescale and discrete models include their enormous computational complexity. In the project the project team shall develop ways to encapsulate microscale results in the form of 'library entries' available to continuum models by ensuring that they are meaningful in a probabilistic sense. The project involves computational studies, algorithm development, and rigorous analysis of the models and the associated error.This investigation shall focus on two applications important for global climate and energy studies, namely, on Enhanced Coalbed Methane (ECBM) recovery, and modeling methane hydrate evolution in subsea sediments (MH). New computational models for these applications and their mathematical analyses are needed for better understanding of various associated hazards and for improved prediction of the fate of methane and its management. Primary impacts of the project are in development of new paradigm of modeling between the models in subsurface and in improved understanding of how porescale phenomena affect the processes at mesoscale. Project results will directly or indirectly aid the modeling efforts in subsurface hydrology, oil- and gas-reservoir modeling, and geological carbon storage projects. In addition, various other disciplines will benefit from the new hybrid discrete-continuum algorithms developed in this project. Other community benefits include the Porescale Benchmark project set up by the investigators, interdisciplinary training of graduate and undergraduates, and development of new senior/graduate level classes and seminars devoted to modeling of processes relevant to global energy and climate issues.