| Title | Thermal Performance Implications of Flow Orientation Relative to Fracture Shear Offset in Enhanced Geothermal Systems |
|---|---|
| Authors | Rita Esuru OKOROAFOR, Roland HORNE |
| Year | 2019 |
| Conference | Stanford Geothermal Workshop |
| Keywords | Flow Orientation, Enhanced Geothermal System, Fracture Heterogeneity, Numerical Simulation |
| Abstract | Fractures and faults are the main conduits for flow in enhanced geothermal systems (EGS). These fractures and faults may have spatial variations for which the aperture is not constant across the fracture plane. The presence of these spatial variations can result in flow channeling and reduced contact area and consequently could impact the thermal performance of the EGS. This study investigated the thermal performance of enhanced geothermal systems considering flow relative to the direction of fracture shear offset and considering spatial variations in the fracture aperture. The system studied consisted of a single fracture with a horizontal injector providing cold fluid, which contacts the hot rock of the EGS, and heat is extracted through a horizontal producer. Several aperture distributions were analyzed with the objective of determining if a direction of flow relative to the fracture shear offset provided better thermal performance. The results showed that where there is continuity across the fracture plane, the flow perpendicular to the fracture shear offset provided better thermal performance than flow parallel to the fracture shear offset. The thermal drawdown was inversely related to the average permeability across the fracture plane and the area contacted by the flowing fluid. |