Laboratory for Earth Energy Systems Research

Design of fracture type reservoirs for clean geothermal energy extraction

We have been developing a design code for fracture type geothermal reservoirs, incorporating a numerical model of hydraulic stimulations based on a fractal network of natural fractures and long-term fluid/heat transfer analyses of thermal extraction stages. The numerical code may be useful for further enhancement of the performance of existing geothermal reservoirs. We are also conducting a pioneering research on potential thermal extraction from deep-seated rock masses in which the temperature and pressure exceed the critical point of water.

Rock/water/ CO2 interactions and reliability assessment for underground sequestration of CO2

Our research team has been performing experimental investigations regarding physical and chemical interactions in rock/water/CO2 systems both for short- and long-term processes in order to assess the potential and reliability of CO2 geological sequestration. It has been demonstrated that absorption of CO2 onto rock pore walls may play an important role in the CO2 injection and storage, by measuring adsorption/desorption isotherms. Numerical computations of CO2 injection are also being carried out to examine the effects of injection parameters and rock/water CO2 interactions on the expansion of a CO2 reservoir, and to understand its mechanical and chemical stability of the rock mass of interest. The ultimate goal of our research team is to establish a CO2 circulation technology for mitigating the emission of CO2 into the atmosphere.

Modeling of mass transport in inhomogeneous rock masses

Modeling of mass transport in underground rock masses is of crucial importance for the development of engineered subsurface systems. It is quite common that underground rock masses of interest possess significant heterogeneities and disorder, and often contains a complex network of fractures, to which the classical theories of flow through porous media such as Fickian law is inapplicable. Our research is targeted at the development of a simple but holistic model for complex flow behavior in inhomogeneous rock masses by invoking a mathematical model of fractional derivative. Specifically, we are aiming to quantify the global characteristics of complex flow on the basis of field tracer responses.