Material Review of Geothermal Resources Extracted from Deep Pilot Wells in the Salton Sea

Abstract There is an increasing demand for energy generation from geothermal resources, which could be challenging if the chemical composition of the geothermal fluid promotes internal corrosion of the downhole tubing. The Imperial Valley of Southern California, near the Southeastern shore of the Salton Sea, is one of the most notorious geothermal resources that contain high-salinity brine, which is one type of corrosive geothermal fluid known for its very low pH. It is usually encountered in deep volcanic and sedimentary systems. Corrosion issues from uniform to microbiologically induced corrosion have been reported by the geothermal power industry due to high-salinity brine and different corrosion mechanisms. In this article, a review of material performance is documented on three casing samples of mechanically lined Corrosion Resistant Alloy (CRA) 625 and clad 680 retrieved from drilling deep pilot wells in the Salton Sea. All samples were exposed to high-salinity brine with high concentrations of carbon dioxide and hydrogen sulfide. The results indicated that the alloy 625 and 680 lined API 5CT L80 downhole tubing exposed to geothermal fluids containing high salinity brine, carbon dioxide and hydrogen sulfide was protected from internal corrosion.