A Portable Multi‐Parameter Fluid Monitoring Unit for Real‐Time Measurements During Well Development and Geothermal Operations

Abstract Monitoring of fluid parameters during well development, groundwater production, or geothermal operation is essential for the understanding of subsurface and well processes. We developed FluMoMax , a portable fluid monitoring unit, that can measure several physicochemical parameters in real‐time, to monitor fluid characteristics and to enable early detection of geochemical processes such as scaling, corrosion, particle mobilization, and oxygen intrusion. FluMoMax integrates sensors for continuous measurement of pH, oxidation–reduction potential, specific electrical conductivity, dissolved oxygen, temperature, turbidity, and density. Optical changes of the fluid can be visually observed through a sighting tube. Various valves are installed for fluid sampling or connecting additional monitoring devices. For high turbidity water, particle filters can be connected. The inline pump regulates the flow rate and ensures backflow without pressure loss into the main production or injection flow line. The device is designed for use in the field, for example, at drilling and well sites. It can operate at process temperatures of up to 120 °C and pressures of up to 10 bar, and was first tested at a drilling site in Berlin under temperatures of up to 107 °C and pressures of up to 7 bar, demonstrating operational reliability for field deployment. FluMoMax provides a robust, and modular solution for multi‐parameter monitoring, thereby improving the understanding of hydrogeochemical dynamics during groundwater extraction and injection.