Project Update: Analysis of Two Sequential Near-Field Well Stimulations at Two Operating Geothermal Fields in Nevada

Abstract

The goal of this ongoing Department of Energy (DOE)-funded Ormat-GeothermEx Wells of Opportunity Project is to use stimulation techniques, guided by geomechanical modeling and analytical methods, to sequentially stimulate two existing wells with long open-hole sections at two operating fields in Nevada. These stimulations have the potential generation impact of up to several MWs at each facility. This project is currently in Budget Period 1 (BP1), with an anticipated completion date of August 2025. Comparative analysis, the results of which will be described during BP2 and BP3, will be used to assess the effectiveness of hydraulic stimulations in different geologic and reservoir management environments, thus a) providing opportunities to adapt and improve methods sequentially from one stimulation to the next, b) providing useful and comprehensive information to the geothermal community about stimulation modeling, methods, costs and results and c) identifying synergies associated with a “stimulation portfolio” approach. Here we provide an update on BP1 activities and the status of the project team’s ongoing efforts to: 1) use all available data to design, forward model, and plan the stimulations; 2) prepare robust designs for stimulation that take advantage of synergies between the 2 proposed wells (for the stimulations to be conducted in BP2); 3) leverage the use of existing technologies, guided by techno-economic analysis (TEA), for stimulation and zonal isolation; and 4) develop geomechanical models and analytical methods to predict and constrain the results of stimulation at a reasonable level of accuracy (as will continue to be vetted and calibrated by hydraulic testing, microseismic and ground deformation data during the stimulations). The project seeks overall to address some of the remaining barriers to the widespread development of geothermal power from enhanced geothermal systems (EGS) (in this case for existing geothermal wells with long open-hole sections, including improving our understanding of why stimulations succeed or fail in a variety of subsurface conditions and implementing and testing well stimulation techniques and zonal isolation methods), thus increasing the willingness of the geothermal industry to adopt and routinely use EGS well stimulation techniques on a commercial basis.