[A-HW25] Near Surface Investigation and Modeling for Groundwater Resources Assessment and Conservation

[AHW25-11] Stochastic inversion of flow and heat transport in heterogeneous porous media

*Doan Thi Thanh Thuy¹, Chuen-Fa Ni^1,2,3, Nguyen Hoang Hiep¹ (1.Graduate Institute of Applied Geology, National Central University, Taoyuan City 32001, Taiwan, 2.Department of Earth Sciences, National Central University, Taoyuan City 32001, Taiwan, 3.Taiwan Polar Institute, National Central University, Taoyuan City 32001, Taiwan)

Keywords:stochastic inversion, Monte Carlo Simulation, Ensemble Kalman Filter, hydro-thermal properties, geothermal system

The permeability, thermal conductivity, and porosity distribution are key factors controlling groundwater flow and heat transport in porous media. The parameter characterization procedure is widely used to understand flow and transport behavior in geothermal systems. As most investigations recognize, this approach relies on accurate measurements, including the propagation of uncertainties due to measurement errors and variation of hydro-thermal properties in heterogeneous porous media. This study aims to quantify uncertainties of hydro-thermal properties by using Monte Carlo Simulation (MCS) and Ensemble Kalman Filter (EnKF). A synthetic two-dimensional aquifer profile is used to assess the accuracy of estimated hydro-thermal properties to account for the variation of groundwater temperature through cross-hole pumping and injection events. Based on calculating mean absolute and square errors for estimated hydro-thermal properties, EnKF generally leads to more accurate hydro-thermal properties estimations than MCS. Furthermore, EnKF balanced accuracy and efficiency, making it the most effective method. This study highlights the strengths and limitations of each method and provides valuable insights for selecting appropriate inversion techniques to quantify uncertainties in geothermal systems. Additionally, the proper distances of installed wells and open screen locations along boreholes are recommended to extract optimal thermal energy in the geothermal system.