摘要
Geothermal energy is used worldwide primarily for generating electricity, space heating and spas. The geothermal resources that have been developed, however, produce only a small fraction of the available energy stored in the upper few kilometers of the earth’s crust(Tester et al., 2006). Although heat is present, rocks throughout most of the shallow crust lack the interconnected permeability necessary to form geothermal reservoirs.