Enhanced Geothermal Systems (EGS) have potential to supply more than 90 GWe of clean and reliable energy to the United States and beyond. One of the keys to commercial success of EGS is that hydraulically stimulated fractures must sustain high conductivity for long durations of 5 years or more. While shear stimulation has been proposed as a solution, the use of solid proppants to sustain fracture permeability holds unique promise in that it is easier to design and to control. Recent field implementation of multi-stage propped hydraulic fracturing for EGS during stimulation has demonstrated energy production from a doublet EGS. However, the minimum proppant pack conductivity (or propped fracture permeability) required for power production, impact of design parameters such as perforation clusters, number of production wells and well spacing on minimum conductivity remains unknown. In addition, it is difficult to control or measure the proppant distribution between fractures in multi-stage stimulations, even though we know that poor distribution will lead to flow heterogeneity and ultimately a risk of thermal short circuiting. To address these unknowns, we seek to identify the minimum propped fracture permeability for hydraulically stimulated fractures that will assure economic energy production from EGS. In this study, we employ models to address the above-mentioned unknowns and thereby provide guidance for designing stimulations for EGS, especially regarding propped fracture permeability (or conductivity). Our analysis is loosely based on the Blue Mountain site by assuming the similar temperatures and depths, 102 perforation clusters, and a two well design. For these conditions, the minimum propped fracture permeability was predicted at 200 D, which equated to individual fracture conductivity ranging from 30 mD-ft to 130 mD-ft depending on the fracture width, to achieve adequate pressures and flow rates for sustained power production. This minimum propped fracture permeability decreased with more perforation clusters. In addition, increasing the number of perforation clusters, production wells, and well spacing increased the power production potential of the system.

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