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

ResFrac shows how buoyancy-driven convection and thermoelastic stresses can surprisingly improve thermal longevity.

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.

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

$Horizontal fracture initiated along weak bedding plane or frictional interface in ResFrac$

Horizontal hydraulic fractures in ResFrac

Horizontal hydraulic fracture propagation is believed to be widespread in shale plays where the frac gradient approaches the overburden – such as the Vaca Muerta, Utica, and Montney. However, horizontal propagation is nearly always ignored in hydraulic fracture modeling. In ResFrac, we are obsessed with ‘getting the physics right’, and so naturally, we extended our simulator to handle horizontal fracturing. The first version of this new capability was released earlier this year. We are eager to start collecting feedback from users, which will help us to fine tune the algorithm and workflow.

Advanced ‘proppant transport in the well’ capabilities are now implemented in ResFrac!

Proppant transport in the well is an intriguing topic that has attracted a lot of interest in recent years [1-8]. Proppant transport processes determine the uniformity of proppant placement, which has a direct impact on productivity. Cipolla et al. estimate that the difference between poor and excellent proppant uniformity is about $2.5M in net present value per well.

Digesting the Bonkers, Incredible, Off-the-Charts, Spectacular Results from the Fervo and FORGE Enhanced Geothermal Projects

I’m out of superlatives – I used them all up in the title. But seriously – Enhanced Geothermal System (EGS) projects have had a really, really good summer. In this article, I summarize the results that have been recently presented by Fervo and FORGE. At their annual Tech Day and in a white paper posted this week (Norbeck et al., 2024), Fervo Energy provided their first update on Project Cape, a Utah project where they are developing 400 MWe of new production over the next two years. So far, fourteen wells have been drilled, and three of them have been stimulated.