About the research

The goal of the project was to investigate the corrosion behavior of materials in the super high-temperature geothermal environment to deepen our understanding of the subject. Corrosion problems were experienced in the first deep geothermal well, IDDP-1 drilled in Krafla, Iceland.  The superheated steam from the well contained several corrosive species, including HCl, CO2, H2S, HF, and H2, and all the materials tested were prone to localized damage.  Root causes and mechanism of the corrosion were not fully revealed after the in-situ geothermal testing, but there is a general lack of research in this field of study at superheated geothermal conditions.  For practical reasons, materials must endure the corrosive environment up to some extent for a long term and economical operation of the geothermal well.

The purpose of this research project was to develop and establish a laboratory testing facility to run corrosion tests in simulated high temperature deep geothermal environments and gain a better understanding of the corrosion behavior of materials in high temperature deep geothermal environments containing HCl, H2S, and CO2. The corrosive fluid was prepared in a laboratory, and corrosion coupon testing was conducted in a series of flow-through reactors at 350°C and 10 bar gauge.  Metal alloys, with and without SiO2 scale, and high-entropy alloys have been tested.  Preliminary results indicate that HCl, H2S, and CO2 contribute to localized damage in carbon steel, but results also indicate that the same corrosive species do not contribute to localized damage in the corrosion resistant alloys.  Comparison of our results to the results from the in-situ corrosion testing done in the IDDP-1 deep geothermal well indicate that HF, H2, under SiO2 scale corrosion or prolonged exposures contributed to the localized corrosion seen in the corrosion resistant alloys tested at IDDP-1.

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