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Geomechanical and Stimulation Effectiveness Modeling for Enhanced Geothermal Systems for the Ormat Wells of Opportunity Project
Minh Tuan TRAN, Logan HACKETT, Allan REYES, Abdul KHAN, Kelly BLAKE, John AKERLEY
[GeothermEx Inc., USA]
The successful development of Enhanced Geothermal Systems (EGS) hinges on the ability to enhance reservoir permeability and productivity through well-targeted stimulation techniques. This study presents the application of geomechanical modeling and stimulation effectiveness modeling to optimize hydraulic fracturing and zonal isolation strategies for a geothermal well: DAC 68-1RD at the Don A. Campbell (DAC) geothermal field in Nevada. These wells are part of the Department of Energy (DOE)-funded Ormat-GeothermEx Wells of Opportunity Project, which aims to stimulate an existing well to unlock additional geothermal potential, with the potential to generate several megawatts of power. The geomechanical modeling workflow integrates high-resolution Pressure-Temperature-Spinner (PTS) logs, geophysical logs, and laboratory testing of core and cuttings to characterize the mechanical rock and hydraulic properties of the reservoir. A detailed 1D Mechanical Earth Model (MEM) was constructed to provide critical inputs for Kinetix modeling, which simulates hydraulic fracture propagation and post-stimulation production improvement. The fracturing model accounts for key physical mechanisms, including geomechanical rock deformation, slurry flow, proppant transport, natural fracture interactions, and the stress shadow effect, to predict the effective fracture geometry. Stimulation effectiveness modeling evaluates the impact of various completion designs and pumping schedules on well productivity improvement. For DAC 68-1RD, the modeling results informed the design of a hydraulic fracturing treatment, including acid spearhead treatments to enhance injectivity in low-permeability volcanic rock. Preliminary results demonstrate the importance of tailoring stimulation strategies to the unique geomechanical and geological characteristics of the well. For DAC 68-1RD, stimulation is expected to achieve a productivity of 10 gpm/psi, enabling production of over 2,500 gpm of 280°F fluid, with an estimated generation increase of 4.9 MW. This study highlights the critical role of geomechanical and stimulation effectiveness modeling in designing and optimizing EGS stimulation treatments. By integrating advanced modeling and leveraging lessons learned from previous stimulations, this project aims to address key barriers to the widespread adoption of EGS technologies and provide valuable insights for the geothermal community.
Topic: Field Studies