For decades, researchers have been able to model and simulate systems of different scales independent of each other; however, the ability to bridge multiple time and length scales between such models has only recently begun to be intensively investigated. The ability to establish a direct connection between the models that are used to simulate the different scales can be expected to provide insight into the extent of heterogeneity that is likely to be prevalent between scales in real systems. Current methods of simulation and modeling generally focus on one particular scale of choice, and any step change in dimension typically necessitates the introduction of new governing equations. Many successful research programs have been based on the constant integration of accurate theoretical modeling and laboratory studies. Concepts developed through simulations can enable a fundamental understanding of the processes in the laboratory while the lab can expose gaps in the fundamental knowledge eager for computational enlightenment.
Modeling multiple dimensions in space is a challenge in and of itself. Not only are we attempting to model all three spatial dimensions, but these spatial dimensions over varying length and time scales adding many added dimensions such as molecular interactions and economics. Kilometer-scale reservoir, and regional, and national-scale economic models of Enhanced Geothermal Systems (EGS) and their potential for U.S. electricity production as well as the coupling of molecular, thermodynamic, reservoir, and economic modeling in a complete package in the area of natural gas hydrates will be presented. Enabled by the incorporation of ab initio calculations on the interactions of guest gas and host water molecules, we have developed a complex set of thermodynamic models for the phase equilibria of hydrates formed from mixtures of gases. These statistical thermodynamic models are incorporated into a reservoir simulator (HydrateResSim) and have been applied to model the Iġnik Sikumi #1 field test performed in early 2012 on the Alaska North Slope by ConocoPhillips, the US Department of Energy, and the Japan Oil, Gas and Metals National Corporation (JOGMEC). The Iġnik Sikumi #1 test was the first field-based demonstration of gas production through the injection of a mixture of CO2 and N2 gases into a methane hydrate reservoir and thereby sequestering CO2 into hydrate form. A model-based history-matching of the gas flow rates from the Iġnik Sikumi field test was conducted to analyze the field trial results.