Geothermal Energy Development in Canadian Cordillera- Structural Uncertainties Scenarios – Case Study

The geologic uncertainties of the Mount Meager volcanic complex in British Columbia, Canada, are analyzed to evaluate the economic viability of geothermal energy. The Mt. Meager volcanic complex was selected for this study due to data availability and need to understand the inhibition for development of a geothermal power plant in the region. This study utilizes a generic petrophysical empirical analysis combined with field reports from the study area to estimate volcanic rock porosity and permeability. Qualitative analysis of fault structure was factored into permeability estimates, which informed the estimated relationship between permeability and mass flow rate for the target formations. Flow rate, outlet pressure and temperature for three different conceptual flow models were simulated and evaluated; an enhanced geothermal system (EGS) utilizing open hole completions, and two lateral well configurations. These simulations considered available geothermal gradient data from the existing exploratory wells as input. An economic analysis was carried out to understand the impact of uncertainties in rock permeability and geothermal aquifer temperature on technical feasibility and economics viability of a geothermal power plant the complex. The EGS implementation, with induced fractures can deliver a mass flow rate of up to 63kg/sec of hydrothermal resource at 197oC from “geothermal sweet spots” in the study area. This could potentially provide power at 20MW capacity power plant from two wells. Lateral (closed loop) wells suffered from lower mass flow rates and resulted in negative NPV due to higher well costs. Sensitivity analyses suggests that permeability is critical for the project economics. De-risking rock permeability with further research and reducing well costs will improve the economic viability of geothermal resource development in British Columbia and should be pursued further.