INVESTIGATING FLUID FLOW BEHAVIOR IN ENHANCED GEOTHERMAL SYSTEM (EGS) WELLS: NUMERICAL AND DATA-DRIVEN APPROACHES

Enhanced Geothermal Systems (EGS) wells utilize artificial fractures created by stimulation to produce hot fluids. Understanding the fluid flow behavior within EGS wellbores is crucial for developing tools that can effectively measure the effectiveness of the fracture conduit in energy extraction over the well's lifespan.

This research contributed to a broader project, which combines analytical methods, numerical simulations, laboratory experiments, and field trials to create and utilize a chloride-based downhole tool. The tool is designed to identify feed zones and measure flow rates in Enhanced Geothermal Systems (EGS) wells through chloride concentration readings along the wellbore. Specifically, this research emphasized numerical simulation and data-driven analysis. The study utilized data and well configurations from the Utah Frontier Observatory for Research in Geothermal Energy (FORGE) field, with the aim of applying the findings to other EGS sites.

Computational fluid dynamics techniques were employed to simulate fluid flow behavior within wellbores across various EGS configurations. Stochastic modeling and machine learning techniques were also utilized to estimate potential measurement errors and build a feed zone flow rate predictor. The results highlight several important phenomena, including blind spots in the mixing zone, downward volume distribution, and fluid flow path alterations caused by periodic turbulence. These findings emphasize the need to consider these factors when designing effective measurement tools. Moreover, simulations involving different tool positions suggest that chemical-based measurements are accurate primarily within the feed zone jet, potentially requiring correction if measured outside the jet. This indicates the importance of incorporating a centralizer in the wireline tool design.

Overall, this research provided insights into fluid flow behavior in EGS wells, reducing uncertainty in EGS well development. The study also proposed a practical tool design for measuring feed zone effectiveness that can be implemented in other EGS sites.