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

Abstract

ABSTRACT: Hydraulic fracturing is applied to extract fluids (oil, gas, and water) from very low permeability rocks. This type of stimulation could develop hot and dry rock geothermal resources. Habitually, those reservoirs are located in the depth of 2.7 Km to 5.5 Km; and at more than 180 °C. This study designs a hydraulic fracturing model in horizontal wells to extract hot water economically, creating high permeable artificial fractures. We aim to investigate the effects of varying fracture-cluster lengths, proppant, and frac fluid types, on hydraulic fracturing treatments using 2D and 3D simulation models. Some parameters such as type of proppant, fracture fluids, number of stages, fracture length, and fracture width are evaluated considering the reservoir’s high temperature and high pressure. Finally, different scenarios are evaluated to know if the hydraulic model is economically feasible to generate electricity with the current price of electricity price, drilling, and completion cost. 1. INTRODUCTION We perform an analysis to evaluate the feasibility of developing an enhanced geothermal system (EGS) project, considering the evaluation and modeling of a horizontal well stimulated by hydraulic fracturing, including fracture fluids and types of proppants that could be used in a frac job. The assessment covers a conceptual representation of a granitoid reservoir, considering a complete economic analysis including NPV, discount rate, reservoir temperature, number of horizontal wells, depth, and electricity sale price. The Department of Energy (DOE) generated an important report called "Geovision, Harnessing the Heat Beneath our feet". This report explains some scenarios concerning the geothermal industry and how will be the forecast for the next 30 years (DOE, 2019). Figure 1 presents the three scenarios explained in the report. The business-as-usual scenario (BAU) explains current and anticipated future trends if the geothermal industry continues on the exact forecast of 2015 conditions. Next, the Improved Regulatory Timeline (IRT) scenario estimates the impacts of reduced geothermal project development timelines and increased discovery rate of geothermal resources due to streamlined regulatory and permitting processes. Finally, the Technology Improvement (TI) scenario assesses the impacts of advanced technology developed aggressivity and the reduction of the cost of some technologies such as drilling, stimulation, logging, and power plants.