Simulation-Based Economic Modeling of Hydraulic Fracturing for Enhanced Geothermal System

Abstract

Enhanced geothermal systems (EGS) are energy sources that support the effort of the geothermal industry toward net-zero targets if adequate and comprehensive studies on the extraction of heat from geothermal reservoirs are applied. Considering a very low permeability, the EGS must be stimulated to extract energy from the deep and hot geothermal reservoir. Implementing EGS is based on shear stimulation of natural fractures by injecting water to induce slip-on self-propping. As a result, hydraulic fracturing is viewed as unnecessary or ineffective to extract hot water; in addition, the use of packers to enable multiple stages is considered technically infeasible because EGS wells are completed open-hole to maximize connectivity to natural fractures, and reliable open-hole packers are not available at high temperatures. Nonetheless, the oil and gas industry has improved stimulation performance in the past two decades, and EGS has not adopted this technological improvement. This section of the book evaluates the stimulation by hydraulic fracturing technically and economically, considering the generation of new fracture sets rather than stimulating natural fractures. The result of this research shows that an optimal EGS model design, including different forms of horizontal length, well spacing, and types of proppants, will improve economic performance.