Rough Size estimation of a thermally fractured zone in an infinite hot rock mass

摘要

Concerning the extraction of geothermal energy from a deep thermal reservoir by the downhole coaxial heat exchanger with a thermally insulated inner piper proposed by Morita et al., we obtained rough estimates of a size of the fractured zone induced by Thermal stresses due to injecting cold water into the hot rock mass through the pipe. We Assumed complete spherical symmetry of the temperature and stress fields. At the rough Estimation, we considered three typical or extreme cases. (1) the fracturing affects Neither the loading capacity of a fractured rock mass nor the temperature distribution Within the formation.