Speaker: Dr. Michael Cardiff
Abstract: The deep subsurface is increasingly being called upon to meet humanity’s growing water, energy, and waste containment needs. This zone — which for fluid flow purposes may roughly be defined as between 100 m and 5 km below land surface — is a region where the process of flow through fractures is likely to contribute strongly to flow and transport, and where dual-domain behavior in both primary and secondary porosity is likely to occur. Similarly, this region represents a domain where complex interactions between fluid flow, rock mechanics, and heat and chemical transport are likely to take place. Engineering applications as diverse as CO2 sequestration, hydraulic fracturing, liquid waste disposal, and geothermal energy extraction will all benefit from a more comprehensive understanding of this hard-to-access part of the Earth where observations are limited and expensive. In this talk, I will discuss field, experimental, and modeling techniques that can be leveraged to gain insights about properties and coupled processes in deep, fractured environments. In particular, I will focus on technologies and experimental designs that hold promise for illuminating the vitally important permeability structure in difficult environments such as fractured or faulted rock. As an example in the field, I will summarize recent work during the hydrogeophysical “PoroTomo” experiment performed at a 2 km-deep geothermal reservoir near Fernley, NV.