Permeability o f fractured tuff as functions of temperature and confining pressure

摘要

Understanding the transport properties of water through fractured rock is critical to predicting and modeling the hydrothermal performance of a geologic nuclear waste repository. Previous studies indicate that intact Topopah Spring tuff from Yucca Mountain, Nevada has a low permeability, approx 1x10~(-18) m~2 (approx 1 microDarcy).~(1,2) A single fracture in the tuff increases the permeability to approx 100 x10~(-15) m~2 (hundreds of milliDarcies). However, fracture healing may occur when high temperature water flows throgh the fracture lowering the permeability by one or more orders of magnitude.~3 We preport progress on laboratory experiments on permeability of fractured Topopah spring tuff as functions of confining pressure, temperature, and water/rock ratio.