The main objective of the work package 2 of the REFLECT project is to characterise relevant fluid properties and their reactions for saline fluids (type C). One of the specific goals was to collect fluid samples from several saline fluids from geothermal sites across Europe, determine their properties, and thus contribute to the Fluid Atlas (WP3). Additionally, the REFLECT team will compare those field data with data from lab experiments performed at near natural conditions.

Samples of type C fluids were taken from several sites in Germany, Austria, Belgium and the Netherlands. The samples were analysed for major and minor ions, dissolved gases and isotopes.

Two thermal water samples were taken by Hydroisotop at the production and injection wells in Insheim on 18th of June 2020. The samples were analysed for their hydrochemical composition, heavy metal and dissolved organic carbon (DOC) content, dissolved gases and stable isotopes of water and gas components (18O, 2H, 34S-H2S, 34S-SO4, 18O-SO4, 13C-DIC, 13C-CO2, 13C-CH4, 2H-CH4). Nitrate and a positive redox potential is present in both water samples when reducing conditions would be expected in a deep geothermal well. On-site measurements showed no oxygen present. It is however possible that air contamination during sampling caused some ammonium to oxidize to nitrate.

The dataset contains analysis results associated with the research project REFLECT. It is a comma separated file (csv) containing the following columns: Location,Country,Description,Laboratory (Lab.),Lab. No.,Sampling date,Temperature at sampling (degC),Spec. electr. conductivity (25 degC) at sampling (muS/cm),Spec. electr. conductivity (25 degC) Lab. (muS/cm),pH value at sampling,pH value Lab.,Dissolved oxygen content (mg/l),Redox potential (mV),Base capacity (pH 8.2) (mmol/l),Alkalinity (pH 4.3) on site (mmol/l),Alkalinity (pH 4.3) Lab. (mmol/l),Sodium (mg/l),Potassium (mg/l),Calcium (mg/l),Magnesium (mg/l),Ammonium (mg/l),Hydrogen carbonate (mg/l),Chloride (mg/l),Sulphate (mg/l),Nitrate (mg/l),Antimony (mg/l),Barium (mg/l),Bromide (mg/l),Fluoride (mg/l),Iodide (mg/l),Lithium (mg/l),Molybdenum (mg/l),Total phosphate (mg/l),Ortho-phosphate (mg/l),Silicon (mg/l),Strontium (mg/l),Sulphide total (mg/l),Aluminium (mg/l),Arsenic (mg/l),Lead (mg/l),Iron total (mg/l),Copper (mg/l),Manganese total (mg/l),Nickel (mg/l),Uranium (mg/l),Zinc (mg/l),DOC (mg/l),Hydrogen (Nml/kg),Oxygen (Nml/kg),Nitrogen (Nml/kg),Carbon dioxide (Nml/kg),Methane (Nml/kg),Ethane (Nml/kg),Propane (Nml/kg),Butane (Nml/kg),Pentane (Nml/kg),Helium (Nml/kg),Argon (Nml/kg),Sum Gases (Nml/kg),Oxygen-18 d18O-H2O (per mille VSMOW),Deuterium d2H-H2O (per mille VSMOW),Deuterium-excess (per mille VSMOW),Carbon-13 d13C-DIC (per mille VPDB),Sulphur-34 d34S-SO4 (per mille V-CDT),Sulphur-34 d34S-H2S (per mille V-CDT),Oxygen-18 d18O-SO4 (per mille VSMOW),Carbon-13 d13C-CO2 (per mille VPDB),Carbon-13 d13C-CH4 (per mille VPDB),Deuterium d2H-CH4 (per mille VPDB).

Methods are described in the accompanying deliverable Fluid data of geothermal sites (type C)

Project summary: The efficiency of geothermal utilisation largely depends on the behaviour of fluids that transfer heat between the geosphere and the engineered components of a power plant. The Horizon 2020 funded project REFLECT aims to avoid problems related to fluid chemistry rather than treat them. Fluid physical and chemical properties are often poorly defined, as in situ sampling and measurements at extreme conditions have proved difficult to date. Therefore, large uncertainties in current model predictions prevail, which are being tackled in REFLECT by collecting new, high-quality data in critical areas. The data is being implemented in a European geothermal fluid atlas and in predictive models to allow recommendations on how to best operate geothermal sites sustainably and to enhance geothermal technology development. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement nº 850626.
Project website: https://www.reflect-h2020.eu/ Cordis website: https://cordis.europa.eu/project/id/850626/de