Stanford Geothermal WorkshopFebruary 9-11, 2026

The deployment of Enhanced Geothermal Systems (EGS) at reservoir temperatures exceeding 300 °C presents unique technical challenges and opportunities for advancing geothermal energy production through the harnessing of higher enthalpy resources. Building on the successful completion and stimulation of the injector well in Phase I, this paper presents the design, testing, and field implementation of the producer well in the world’s first propped EGS doublet at ultra-high temperature conditions at Newberry Volcano, Oregon. A segmented stimulation strategy with a hybrid fluid design including crosslinked fluids and a hybrid completion in terms of wellbore to reservoir connection was developed for the producer well, incorporating field experience from the injector stimulation, real-time diagnostics and adaptive planning of treatment volumes. The approach integrates distributed temperature sensing (DTS) and distributed acoustic sensing (DAS) via permanent fiber optic installation in the injector well, enabling cross-well monitoring during stimulation of the producer. Nano tracers were deployed in the producer well to provide flow path characterization, while micro seismic activity was monitored using multiple array set ups and fiber inferred DAS data. The Phase II program emphasizes the importance of iterative design, real-time data connection, and advanced stimulation diagnostics to optimize fracture propagation and maximize the probability of hydraulic connection between wells. This work documents the methods, results, and lessons learned from the Phase II completion and stimulation, culminating in the anticipated connection of the wells to enable future circulation and heat harvesting. The findings provide critical insights for the advancement of next-generation EGS technologies at ultra-high temperatures and pave the path to de-risking technologies for superhot rock.

Topic: Enhanced Geothermal Systems