| Title | Analyzing convective cells behavior in geothermal reservoirs: insights and implications for resource development |
|---|---|
| Authors | Giordano Montegrossi, Mirco Lupi, Maurizio Cei |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | In hydrothermal convection systems, most of the heat is transferred by the convective circulation of water or steam rather than by thermal conduction through solid rocks. Convection occurs in rocks of adequate permeability due to the buoyancy effect of heating and consequent thermal expansion of fluids in a gravity field. The heated fluid tends to rise, while the denser, cooler fluid tends to descend elsewhere in the system. The presence of multiple steady states of convection patterns characterized by various values of the Nusselt number may lead to a non-homogeneous temperature distribution also in naturally convected geothermal reservoirs, due to different efficiencies in transferring heat to the surface. The reservoir geometry, the heat source shape, the inflow of deep fluids and the recharge pathways greatly affect convective circulation, altering the shape of the convective cells. Faults and seals present in the reservoir may influence the convective paths. A permeable fault in one valley can also induce cross-range flow if there are no equally good upflow paths in the adjacent valleys. When bulk permeability is sufficiently high, additional deep circulation cells develop in neighboring valleys, diverting heat and fluid from the fault and consequently reducing temperatures in the fault itself. To add complexity, production and reinjection wells significantly impact the convective flow path, which changes over time during exploitation; thus, an accurate modeling of the reservoir convective cells is essential for an optimal well placement and reservoir exploitation. |