9316336 Evans The PI will perform experiments to measure the change of porosity and permeability with time in rocks saturated with water at high temperature and pressure. Cracked rock samples will be saturated with fluid and heated to 400-600 C at various combinations of fluid and confining pressure. Permeability will be measured before, during and after the hydrothermal treatments. Extensive microstructural analyses will be performed to understand the changes of microstructure and pore geometry that occur, including measurements of mean values and distributions of crack length, crack aperture, and orientation. Such measurements will show the evolution of the pore space, and can be compared with stereological measurements of natural samples and samples that have been thermally cracked without pore fluids. With a new apparatus he will measure the evolution of the permeability with time while the samples are under hydrothermal conditions. Some experiments will also be done with triaxial loading to test the effects of non-hydrostatic stresses. ****
