A versatile fluid-chemical monitoring unit (“FluMo”) has been developed that enables online and in-situ measurements of a variety of physico-chemical parameters at different surface locations of a geothermal fluid loop. Sensors are provided for pressure, temperature, volumetric flow-rate, density, pH-value, redox potential and oxygen content. Additionally, two fluid samplers have been installed to collect fluid and analyze the solution composition. All devices are mounted on a rack allowing easy transfer of the apparatus to other geothermal plants. The purpose of the system is to monitor a compositional variability of the produced fluid and chemical processes potentially occurring within the plant. This information is of paramount importance as such reactions might lead to failure of plant components through corrosion and scaling and/or damage the reservoir upon fluid reinjection and thus decrease injectivity.

The Fluidflow Monitor and Reactor Unit (FluMoRe), consisting of two 50 L stainless steel vessels, enables storage and monitorable flow of a fluid under high-pressure/high temperature conditions by pumping it from one vessel two the other allowing online measurements and sampling. The vessels are equipped with several analytical sensors and can also be used as reactors.

The Fourier transform infrared spectrometer (FTIR) BRUKER, Vektor can be used to obtain an infrared spectra of a solid or liquid to identify inorganic and organic species in the samples. A special high pressure and temperature cell can be connected to simulate geothermal conditions during measurement.

The portable fluid monitoring system has been developed for continuous in situ measurements of physico-chemical parameters of produced water e.g. borehole tests and geothermal fluid loops. Temperature, specific electrical conductivity, pH-value, dissolved oxygen and redox potential (all Endress + Hauser) can be measured simultaneously at pressures and temperatures up to 9 bar and 120 °C, with two filters connected in parallel upstream preventing any clogging of the flow-through cell.

Model: Thermo Scientific MaxQ 4000

Study of water-rock interaction under oxic and anoxic conditions at moderate temperature from 10 °C above ambient to 80 °C. Continuous shaking or timed operation from 0.1 minute to 999 hours can be set with speed ranging from 15 to 500 rpm.

Model: MBraun Unilab

The glovebox allows working in an argon-protective atmosphere, which ensures the preparation and performance of experiments under anoxic conditions.

Technical data:

• Closed loop recirculation
• Moisture < 1 ppm
• oxygen < 1 ppm

Model: Bruker Tracer 5

p-XRF is a non-destructive simple to handle elemental analysis technique. It provides a real-time quantification of many elements from Mg to U, which makes it a handy tool on drilling sites. Furthermore, scales can be identified quickly, and suitable sampling locations can be found by screening cores and outcropping rocks.