Denver SPE General Meeting: From Heel to Toe: Engineering Uniform EGS Injection

Abstract:
EGS circulates cooler water through hydraulically connected horizontal wells, creating a subsurface heat exchanger. Ideally, the injection is evenly distributed across the fracture network to promote uniform thermal drawdown; however, fracture variability and wellbore friction can concentrate flow in high-conductivity pathways or heel-biased stages, reducing sweep efficiency and accelerating thermal breakthrough. Modeling indicates conformance control providing uniform injection can increase 30-year power generation by 50%. This presentation summarizes surface qualification testing by GTO Technologies of a second-generation casing sleeve, pump-down actuation system, and high-temperature tractor designed to deliver uniform EGS injection independent of fracture conductivity. The system preserves full inner diameter from heel to toe and avoids telescoping ball seats while providing regulated flow through an outflow control device. The larger casing inner diameter also reduces parasitic pumping losses from wellbore friction and supports higher injection rates at lower pressures.