Quantification of bore path uncertainty in borehole heat exchanger arrays using adaptive anisotropic stochastic collocation
Generally, models of geothermal systems are created under the assumption that bore paths are (usually) perpendicular according to their planning. In reality, however, borehole paths are subject to uncertainty because they are often deflected from the planned drilling path by geological anisotropies. In this paper, we present a detailed approach for the simulation-based assessment of the impact of borehole path uncertainties in borehole heat exchanger arrays on geothermal plant performance metrics, especially in geothermal storage operation. For this purpose, an adaptive, anisotropic stochastic collocation method is used, which proves to be suitable and computationally efficient for performing uncertainty quantification of geothermal applications. We also discuss the importance of considering different types of geometric variations, including nonlinear variations that can scale with drilling depth, to reflect the range of possible uncertainties. In addition, we address the challenges associated with sampling possible geometries during the interpolation process. Overall, our work aims to develop an understanding of the magnitude of the impact of borepath uncertainties and to improve methods for uncertainty quantification in the context of geothermal energy systems.