Application of Dissolved Noble Gas in Shallow Groundwater in Characterizing Deep Thermal State of Blind Geothermal System

Abstract

For areas without surface thermal displays (such as hot springs, fumaroles, mud pools, and geysers), i.e. blind geothermal systems, locating and characterizing deep geothermal resources is challenging, and drilling and exploration economics are high in the absence of target steering In addition, the control depth and range are limited, most geophysical explorations are difficult to capture the motion process of deep geothermal fluids, and the detection results have multiple solutions. The development of research geochemical tools is very important for the limitation of deep thermal state. Noble gases hold three main characteristics: high volatility, chemical inertness, and significant differences between different endmembers, and are useful tools for deep geothermal characterization. In our stuty, we carried out a complete set of elemental content and isotopic ratio tests for noble gases (He, Ne, Ar, Kr, Xe) in the groundwater of Wudalianchi, and conducted source analysis (atmosphere, crust, mantle, etc.) and geological process analysis (recharge) of noble gases. Equilibrium, degassing equilibrium, diffusion, boiling vapor-liquid differentiation, etc.), and studied the ability and mechanism of shallow groundwater to capture deep thermal signals. This study holds scientific significance for expanding the application of noble gases in the field of geological fluid tracing and geothermal exploration, and can provide reference for other similar geothermal exploration in blind geothermal system areas.