  To maximize value from an EGS system, engineers need to optimize flow rate,
well spacing, and well configuration. Numerical simulations yield interesting
and surprising results regarding the effect of coupled processes on long term
thermal performance. Thermoelastic fracture opening and propagation can have a
significant negative effect on the uniformity of flow. On the other hand,
interactions between fracture opening and buoyancy driven fluid circulation
cause downward fracture propagation during long-term circulation that greatly
improves the thermal longevity of the system. Passive inflow control design can
significantly mitigate the negative effect of thermoelastic fracture opening on
flow uniformity, while maintaining the positive effects of thermoelastic
fracture opening and propagation on flow rate and thermal longevity. Overall,
simulations suggest that an EGS doublet with 8000 ft laterals at 475' F, using
inflow control at the production well, could sustain electricity generation
rates of 8 to 10 MWe for more than 30 years. Without inflow control, 6 to 8 MWe
over 30 years is possible; however, there is greater risk of uncontrolled
thermal breakthrough.
