Copper precipitation as consequence of steel corrosion in a flow-through experiment mimicking a geothermal production well

dc.contributor.authorRegenspurg, Simona
dc.contributor.authorGeigenmüller, Ives
dc.contributor.authorMilsch, Harald
dc.contributor.authorKühn, Michael
dc.date.accessioned2018-04-19T08:51:13Z
dc.date.available2018-04-19T08:51:13Z
dc.date.issued2017
dc.description.abstractDecreasing production rates and massive precipitation of native copper (Cu(0)) were observed in the production well at the geothermal research facility Groß Schönebeck (Germany). The Cu precipitates filling up the well are a product of an electrochemical corrosion reaction between dissolved copper (Cu2+, Cu+) in the brine and iron (Fe(0)) of the carbon steel liner. It was hypothesized that this reaction occurs not only within the borehole, but also on the outside of the casing at contact between casing and reservoir rock as well as in the pores of the reservoir rock. To verify the assumption of potential clogging of the rock pores as well as to quantify the reaction and to determine reaction kinetics, a flow-through experiment was designed mimicking the reaction at depth of the well between sandstone samples (24 cm3 Fontainebleau), steel (carbon steel or stainless steel), and artificial formation water containing 1 mM Cu2+ at oxic or anoxic (O2 < 0.2 mg/L) conditions in dependence of temperature and salinity. Obtained experimental data served as input for a numerical reaction model to deepen the process understanding and that ultimately should be used to predict processes in the geothermal reservoir. Results showed that (1) with increasing temperature, the reaction rate of the electrochemical reaction increased. (2) High amounts of sodium and calcium chloride (NaCl + CaCl2) in the solution decreased the overall reaction inasmuch more Fe and less Cu was measured in the salt-poor solutions over time. (3) Strongest oxidation was observed in oxic experiments when not only native copper but also iron hydroxides were identified after the experiments in the pore space of the rock samples. (4) No reaction products were observed when stainless steel was used instead of carbon steel to react with the Cu2+ solution. A numerical flow-through reactor model was developed for PHREEQC based on the assumption that Fe(0) corrosion is kinetically controlled and subsequent Cu(0) precipitation occurs in thermodynamic equilibrium within the investigated experimental set-up. Calculated coefficients of determination comparing measured and simulated reaction rates for Fe and Cu underline the validity of the approach.en
dc.identifier.eissn2195-9706
dc.identifier.issn2195-9706
dc.identifier.urihttps://depositonce.tu-berlin.de/handle/11303/7666
dc.identifier.urihttp://dx.doi.org/10.14279/depositonce-6856
dc.language.isoen
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subject.ddc550 Geowissenschaften
dc.subject.othersaline fluidsen
dc.subject.otherelevated temperatureen
dc.subject.othercopperen
dc.subject.othercarbon steelen
dc.subject.otherflow-through experimentsen
dc.subject.otherelectrochemical reactionen
dc.subject.othercorrosionen
dc.subject.otherPHREEQC modelingen
dc.titleCopper precipitation as consequence of steel corrosion in a flow-through experiment mimicking a geothermal production wellen
dc.typeArticle
dc.type.versionpublishedVersionen
dcterms.bibliographicCitation.doi10.1186/s40517-017-0069-9
dcterms.bibliographicCitation.issue1
dcterms.bibliographicCitation.journaltitleGeothermal Energyen
dcterms.bibliographicCitation.originalpublishernameSpringer Nature
dcterms.bibliographicCitation.originalpublisherplaceBerlin
dcterms.bibliographicCitation.volume5
tub.accessrights.dnbfree
tub.affiliationFak. 6 Planen Bauen Umwelt::Inst. Angewandte Geowissenschaftende
tub.affiliation.facultyFak. 6 Planen Bauen Umweltde
tub.affiliation.instituteInst. Angewandte Geowissenschaftende
tub.publisher.universityorinstitutionTechnische Universität Berlinde

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