Methods and system for geothermal energy harvesting using both conductive and convective heat transfer are provided. A geothermal well is provided with inlet and outlet wellbores and an interconnecting wellbore therebetween, the interconnecting wellbore fluidly connected to a plurality of fluid conduits, such as fractures. The interface of the wellbore and fractures with the surrounding earth may be impermeably sealed with a sealant. A heat transfer fluid is circulated throughout the system to extract thermal energy from the earth by conduction, as well as by convection. By providing the plurality of fluid conduits and by utilizing convective as well as conductive heat transfer, the rate of energy extraction may be increased.