Process for injecting terrestrial heat of CO2 mining waste high-temperature gas reservoir

The invention relates to the field of gas reservoir development and geothermal energy development, and proposes a process for injecting terrestrial heat of a CO2 mining waste high-temperature gas reservoir in allusion to such development statuses as short effective production period of a high-temperature gas reservoir, gas field well net waste and bad waste of ground pipe transmission facilities. The method can quickly realize recovery of high-temperature waste gas reservoir pressure and efficient mining of geothermal energy through changing the working systems of injecting and mining wells in different phases. In the geothermal mining process, the method can realize the following effects: (1) in earlier stage of injection, the final mining rate of the gas reservoir is improved by a gravity differentiation effect of CO2 and natural gas; (2) after the pressure of the gas reservoir is recovered, a high-purity CO2 gas reservoir can be formed to realize circular injection and mining of supercritical CO2 so as to develop the geothermal energy; and (3) in later stage of developing terrestrial heat, when the gas reservoir has no terrestrial heat developing value, most CO2 can be embedded in the gas reservoir for future use. The method has important significance on improvement of the gas reservoir recovery ratio, later secondary development of the gas reservoir, capacity conversion of oil and gas reservoirs, greenhouse gas embedding and the like.