The invention relates to the technical field of
geothermal energy development and utilization, and discloses a multi-well cooperative enhanced heat exchange method for medium-deep layer
geothermal energy waterless exploitation. According to the method, an inverted-cone-shaped heat conduction network comprising a center main heat collecting well, an auxiliary heat conduction well array and a temperature-sensitive
phase change heat conduction bridging grouting area is constructed. During operation, a low-temperature working medium is injected into the central well to reduce the temperature of the grouting area to be below the
phase change temperature,
phase change shrinkage of the microcapsules is triggered, the high-thermal-
conductivity filler is induced to make contact with one another, a thermal-
conductivity seepage network is constructed, and the
thermal conductivity of the grouting area is converted into an enhanced state from a
ground state. The auxiliary heat conduction well gathers far-field heat and transmits the far-field heat to the center well according to the gravity assisted
heat pipe principle. According to the invention, the
microstructure evolution of the material is driven by using a temperature field, the self-adaptive adjustment of the heat
conductivity is realized, the heat removal volume is obviously enlarged, the heat loss of the shaft during the non-operation period is reduced, the
geothermal energy exploitation efficiency is improved, and the reverse loss of the heat of the working medium in the shaft to the stratum during the non-operation period is reduced.