Deep geothermal single well system is one of the geothermal energy utilization mode that only takes heat without consuming water. Compared with the traditional mode, this system avoids the problem of difficult sandstone reinjection, which can greatly reduce drilling costs, and is applicable to a wide range of geological conditions. Geothermal single well system can be divided into close loop and open loop system. The latter exchanges heat with the aquifer by convection heat transfer and mass transfer, the heat output is higher than that of the close loop system through conduction heat transfer. In this paper, a three-dimensional unsteady flow and heat transfer model is established for the open loop coaxial casing of the geothermal deep single well with a packer, the effect of the density of geothermal water on the aquifer temperature distribution and heat output of the single well under different aquifer permeability is numerically simulated. The result shows that when the permeability of the aquifer is greater than 1.0E-12 m2, the permeability has a great influence on the heat output of a single well, while when the permeability is less than 1.0E-12 m2, the permeability has little effect the heat output too much. The permeability has little effect on the heat output of a single well. The results can be used for calculating the heat output of a single well in different aquifers.
Keywords open loop, deep geothermal single well, aquifer, permeability, density, heat output