Enhanced Geothermal Systems

Multistage fracturing is a breakthrough for EGS - dramatically improving energy production per well

ResFrac's fully-coupled fracturing and reservoir simulator is ideal for simulating hydraulic fracturing and long-term circulation in multistage EGS designs

Fracture propagation

3D fracture initiation and propagation, interaction between wells, stress shadowing, proppant transport, complex fluid additives and non-Newtonian flow, diverters, and wellbore dynamics.

Fracture reopening during circulation

Ability to simulate the mechanical opening of fractures, and the associated increases in fracture conductivity, induced by cooling during long-term fluid circulation.

Decision support tools

NPV maximization using ResFrac's economics engine and cloud-based optimization tools.

The ResFrac team offers authentic, deep expertise in multistage fracture design optimization and Enhanced Geothermal Systems

Fervo Energy engineers use ResFrac to develop breakthrough EGS stimulation designs, enabling Project Cape record-breaking flow rates exceeding 100 kg/s per well, a 3x improvement on the previous ‘best ever.

What are Enhanced Geothermal Systems?

Source: SMU Dedman College of Humanities & Sciences Geothermal Lab

Enhanced Geothermal Systems use hydraulic stimulation to produce from high-temperature, low permeability resources

Geothermal production potential is huge across the United States and globally. However, production is limited by insufficient natural permeability in most resources. Analogous to the shale revolution, EGS promises to unlock these resources by enabling much higher flow rates and low power costs.

Multistage stimulation resolves the problems that have historically limited EGS performance

Traditional EGS designs have been performed in a single stage, without proppant. These designs suffer from flow localization, where the fluid flows into a relatively small number of flowing pathways. In formations lacking large, naturally conductive faults, these designs have suffered from insufficient unpropped conductivity. Shale-style ‘plug and perf’ limited-entry completions with resolve both of these problems.

Key technical references

Almarri, M., M.J. AlTammar, G. Fowler, and K. Alruwaili. Utilizing Thermally Controlled Fluid to Improve Cluster Uniformity and Efficiency. SPE Unconventionals Conference in the Middle East.

Fowler, G., and M. McClure. 2021. A Feasibility Study on Three Geothermal Designs: Deep Closed-Loop (with and without Conductive Fractures) and Open-Loop Circulation Between Multifractured Laterals. GRC Transactions.

Li, T., S. Shiozawa, and M. McClure. 2016. Thermal breakthrough calculations to optimize design of a multiple-stage Enhanced Geothermal System. Geothermics.

McClure, M. 2023. Technical Barriers for Deep Closed-Loop Geothermal. This article was originally posted as a ResFrac blog post, and published on arXiv in March 2023.

McClure, M. 2023. Thermoelastic fracturing and bouyancy-driven convection- Surprising sources of longevity for EGS circulation. This article was originally posted as a ResFrac blog post, and published on ArXiv in August 2023.

McClure, M. 2023. Calibration Parameters Required to Match the Utah FORGE 16A(78)-32 Stage 3 Stimulation with a Planar Fracturing Model. Fourty-Eigth Workshop on Geothermal Reservoir Engineering, Stanford, CA.

McClure, M. 2021. Guest Editorial: Why Multistage Stimulation Could Transform the Geothermal Industry. Journal of Petroleum Technology.

McClure, M. 2012. Modeling and characterization of hydraulic stimulation and induced seismicity in geothermal and shale gas reservoirs. PhD Thesis, Stanford University.

McClure, M., and R. Horne. 2011. Investigation of injection-induced seismicity using a coupled fluid flow and rate/state friction model. Geophysics.

McClure, M., and R. Horne. 2014. An investigation of stimulation mechanisms in Enhanced Geothermal Systems. International Journal for Rock Mechanics and Mining Sciences.

McClure, M., R. Irvin, K. England, and J. McLennan. 2024. Numerical Modeling of Hydraulic Stimulation and Long-Term Fluid Circulation at the Utah FORGE Project. Fourty-Ninth Workshop on Geothermal Reservoir Engineering, Stanford, CA.

McClure, M., C. Kang, and G. Fowler. 2022. Optimization and Design of Next-Generation Geothermal Systems Created by Multistage Hydraulic Fracturing. SPE Hydraulic Fracturing Technology Conference and Exhibition.

Norbeck, J., M. McClure, and R. Horne. 2018. Field observations at the Fenton Hill enhanced geothermal system test site support mixed-mechanism stimulation. Geothermics.

Shiozawa, S., and M. McClure. 2014. EGS designs with horizontal wells, multiple stages, and proppant. Thirty-Ninth Workshop on Geothermal Reservoir Engineering, Stanford, CA.

Singh, A., G. Galban, M. Mcclure, K. Briggs, J. Norbeck. 2025. Designing the Record-Breaking Enhanced Geothermal System at Project Cape. Unconventional Resources Technology Conference.

Wang, Z., M. McClure, and R. Horne. 2009. A single-well EGS configuration using a thermosiphon. Thirty-Fourth Workshop on Geothermal Reservoir Engineering, Stanford University.

Recent content from the ResFrac blog

Abstract illustration with multiple outlined maps over a green-to-yellow gradient and light beams.

The influence of well configuration on water loss in Enhanced Geothermal Systems

Recently, ‘water loss’ has been a hot topic of discussion for EGS. Fervo reported that they have been producing only 70% of the fluid volumes that they have been injecting at their Project Red. The FORGE project reported a roughly 10% water loss rate. Because projects will have finite water rights, these results have led to concern that growth of EGS will be limited by excessive water consumption. This is a valid concern, and water availability is a legitimate factor in site-selection and project engineering. However, I believe that the problem has been overstated.

Large conference room with a speaker presenting a slide deck to an audience seated around circular tables.

2026 ResFrac Annual Symposium Recap

On June 25, 2026, we got the ResFrac community together both in-person at the ExxonMobil campus in Spring, Texas, and virtually around the globe for our Annual Symposium. With our community growing as fast as it is, the energy in the room was absolutely buzzing. We had a jam-packed day of operator case studies, deep-dive technical sessions, and some incredible geomechanical insights from industry legends.

ResApps FracTest interface showing a Stress interpretation section with an Auto-interpret button and contact options, next to a Stress Diagnostic Chart.

FracTest – An Online Tool for DFIT Interpretation

This week, we are releasing FracTest, a web-based application for interpretation of diagnostic fracture injection tests (DFITs). FracTest is available at resapps.resfrac.com, alongside our other two ResApps, StageOpt and IntTest. DFITs are small-volume fracture injection tests used to estimate stress, pore pressure, and permeability. These quantities form the foundation of the fracture and reservoir engineering work that we do in ResFrac, and so we view DFIT interpretation as one of the most important parts of our workflow.